I am questioning the assertion that any particular kind of subsistence is immune from the pull toward the evils for which we know this civilization.
Before we keep going, I'd like to ask you to not use the terms "good/evil" or "good/bad". Those terms are belief-based concepts, not real world action/reaction observations. It becomes hard to talk about shared observations of reality when they become obscured by ethics. If you think destruction of the environment is "bad" then please refer to it as "destructive" rather than "bad". If you say "destructive" I see the action/reaction of something happening in the real world. If you say "evil" it comes across as a religious statement, which is not based on actions, but personal beliefs. We are building a common language with which to discuss shared observations of reality, and beliefs and concepts like good/bad/evil just get in the way. I don't think civilization is "evil" or "bad" or "wrong". They are destructive forces of nature that cause mass extinctions. Asteroids do that too.
None of these ways are proof against negative environmental impacts. And too many people adds up to an environmental problem in the long run, no?
The proof is in the pudding. There is little to no evidence of horticulturalists or hunter-gatherers that devastated their environments. Most of the classic examples like the Pleistocene die-off have been debunked. I can't claim that this never happens, but we have little to no proof that they did. We do have proof that these cultures had population complexities and higher rates of conflict. No one has ever claimed that there is a perfect way for humans to live; there are just ways we understand had better impacts on the environment and our own communities.
Horticulture can mean "more people" but it doesn't necessarily mean "too many people". I think we have a hard time understanding horticulture and hunter-gatherer land management because we are so used to seeing that as a way of controlling the food supply only for humans.
However, this is not true. Horticulturalists do not build fences. They do not take away the ability of others to reap the benefits of encouraging more growth. An increase is "food production" for horticulturalists also means an increase in food for all other mammals that eat in a similar fashion as we do. Horticulture is not necessarily labor intensive either. The point is letting nature do the work for you. Starting a fire and watching it burn is very different from chopping down all the trees in a region and then tilling the soil and irrigating it.
Horticulture either creates more biomass or more biodiversity while not destroying the soil, which all life is dependent. Horticulturalists can create more biomass, such as the 2000 year old cedar trees and runs of salmon so thick you could walk across the top of a river on them. More fish means more bears for example. This is not an increase in food production, it's an increase in particular forms of biomass. Horticulture mostly uses fire to return nutrients to the land faster than if they were to break down without it. It's not destructive, it's an increase of the speed in which nutrients become bioavailable. Burning a field is similar to the flooding of a river in that regard. Horticulture is multi-habitat management. This means you've got fields, savannahs, woodlands, forests and climax forests. The most biodiverse places are where two or more habitats meet. Biodiversity requires these edges. Horticulture maintains these edges and encourages them.
The term intensification, meaning an "increase in food production/efficiency", is a construct of a civilizational paradigm in which humans are thought to be the sole land managers of a landscape. This mentality is carried over into permaculture, which is why it is not worth the hype it gets. Horticulture is not about controlling the food supply for humans only. It's about increasing the abundance for everyone; humans and other-than-humans.
This is not to say that horticulturalists haven't or could not completely fuck up their environment. It's just not very likely. This is not true of agriculturalists. With agriculture, it's a given. Again, the proof is in the pudding. Agriculturalists (full-time agriculture) has proven to be destructive every time. A great book that expands on Jared Diamond's book "Collapse" is called "Dirt: the erosion's of civilization".
But honestly, I think I know what you're getting at. You're talking about Empire and Daniel Quinns the "One Right Way" meme as the inspiration that took over agriculturalists into this unsustainable wreck. It took a ruling class to convince their slaves that agriculture was the one way that everyone should live. Is this what you are wanting to articulate? If so, I think we would all agree. I don't think it was agriculture alone. And we certainly didn't get to where we are with plain old agriculture. None of the other civilizations bounced back the way ours did. A great example of a horticultural society post-civilization is Martin Prechtel's books about the Mayans. They didn't "disappear" to a higher vibration of existence as the racist books of the Celestine Prophecy want us to believe. They just stopped full-time farming. Lol. And their spiritual concepts become such that building civilization's were not possible. So there is something clearly different about our culture than other civilizations that came and went. However, full-time agriculture always leads to increase in population and always to a hierarchy. This doesn't necessarily lead to the "One Right Way" mentality that our civilization has. In that regard, agriculture is not an inherent cause for the One Right Way meme. But while all other civilizations did not create a global mass extinction, they sure as hell created a localized one.
As a related aside:
The Northwest Coast horticulturalists had a hierarchy, but their potlatches and "slave" rank were not the way you described, or even Jason described. Nancy Turner covers a little bit about this in the "Earth's Blanket". The NW coast did not have a class system, but a ranking system. "Slavery" in a ranking system is not like the slavery we are aware of in the context of our own culture and in fact, "Slavery" is not an accurate term to describe the rank for which it stands. But that's a complex discussion for another thread. The potlatches were actually a way of removing excess wealth. It was "Indian Christmas" where wealth was distributed to the people who needed it, and the rest was destroyed. This changed dramatically and turned violent with the encroachment of settlers. Think about it this way: Most of what we know anthropologically about the NW came in the form of Lewis and Clark's minimal journals. 90% of indigenous people here died in 1833. Franz Boas, the father of NW Coast anthropology came here in the late 1890's. 70 years after their apocalypse. Potlatches and Slavery at that time were heavily influenced by civilization and the collapse of the culture here. What most people know about those practices come from an apocalyptic native culture. We can't really re-construct what things were like before, but there is evidence that alludes to things being very, very different than Franz Boas and others described. Also the so called "Big Man" or "Chiefs" had no say in any kind of military actions what-so-ever. This is directly opposed to our class system where the wealthy absorb it all and simultaneously control the military.
As another related aside:
Anthropologists are quick to say that NW Coast Indians had the concept of land ownership. This again, is a projection of our own cultural memes. They had families of "land stewards" who had more say than anyone else on who, how many people and in what quantity they could harvest from a particular piece of land. They didn't "own" the land; they tended it. If the head of a family who "owned" a piece of land let too many people harvest and fucked it up in any way, if was considered a crime punishable by death. Contrast this with our culture, where you can completely obliterate a piece of land and make a million dollars in the process.
There are a zillion kinds of subsistence strategies and they can look very different and work differently in many places. What we can notice though, are tendencies in the subsistence strategies. Agriculture tends to destroy soil. Doesn't mean it always does. Horticulture tends to encourage climax forests and build soil. Doesn't mean it always does. I don't think anything is as Black and White as our culture wants to think it is. The irony is that more and more these "immediate-return hunter-gatherers" are being relabeled as "hunter-gatherer-horticulturalists" when more closely examined. The lines are all very blurred.
I also think that rewilding is not about running away and trying to live as an immediate-return hunter-gatherer, but rather going backwards from where we are now. Planting forest gardens, burning instead of tilling. Raising cattle, free ranging them and rewilding all the things that we domesticated along the way. This means low-intensity agriculture as well (without a plow or irrigation).
Oh and to your question, did plowing/monocropping grains make this civ possible? Sure. But there were other civs. Norte Chico (Caral) was based on fish-orchards-veggies. No grains. They did have irrigated fields... and did not ruin the land.
Many people claim that the NW Coast culture was a civilization. But again, this obscures a lot more about what we mean when we say civilization. These cultures had large populations and lived from fishing site to fishing site. They were still somewhat nomadic even in their sedentarianism. We reserve the term civilization specifically for agrarian-based cities. Villages are not cities. This I think shows us that we could have something similar to civilization in terms of large villages but not cities. I think it's important to keep the definition of civilization to agrarian-based cultures for our purposes. In that regard, a fishing/orchards/veggies based horticultural society would not fall under our definition of "civilization".