Given that scraping for AI training has been made legal in several places in the world, with various level of constraint, it's a stretch to assume the author is a thief for using AI to produce the content (or using copilot, or using Photoshop's "intelligent" tools) without knowing anything more. Your post is indeed controversial, as would someone posting that gun owners are criminals (or worse, in all caps). That's absolutely something you can think, but it might spark reactions if said on a politics-free international board.
With regards to quality, I also wouldn't buy "generic garbage", irrespective of how it was produced. Honestly, would you eagerly buy bland, generic garbage made by a non-caring author just putting out slop on DMsGuild? I think you wouldn't,so I guess the original question was more about equal-quality results. Would I buy a garbage AI product, no, of course, same as human-produced garbage product. I don't think it says anything about my stance on AI-generated products and the question about buying them. If the initial question's intent was to analyze our stance on AI, I think a better question would "would you rather suffer from an illness or buy an AI-generated drug"? That would be, I think, a better test than asking if we love AI-generated content enough to pay for them even if they are bad. To that question, I guess 99.9...% of the people would say no.
Is AI able right now to produce interesting content, that's another question. It was an argument a few years/months ago about AI image generation. Many people at the time said that AI was producing garbage images, and it was true, the technology was (and still is) nascent and it was interesting to follow but not really usable. But if you look at the thread about AI art for character generation on this board, you can see that the quality has improved substantially over the last two years, enough to be used in some cases. For example, since I haven't and won't commission artworks for my campaign journal, that takes the form of an in-universe newspaper, the choice is between "text-only" or "AI-illustrated", and I think we're past the point were AI images would detract from the prop.
I think it's the same with text. Maybe right now, AI can't produce content on par with with commercial handmade products, but it won't necessarily be the case over the next centuries, decades, years or, as seen with images, months. In this case the question would be: would you buy a good quality AI-made Castle Greyhawk or pass? I don't think so, because I'd rather run the AI-generating bot to help me write adventures from my group for free instead of paying, unless the technology is still in its infancy in a way that good content is possible but would need heavy hand-editing (so in this case, the AI would simply help the writer, as an helper not unlike a grammar checker, or if a good product was something like 1 in a thousand, and I might pay a little for the work of sorting out the chaff. Assuming AI produces consistently good product, I wouldn't buy it but rather use the tool on my computer. As with any commercial offer, I wouldn't pay more than I think buying the product will be useful (in this case, save me time), and compare my valuation of the time saved to the price.
On the morality of self-justice especially to punish people who might have done no wrong (if creating something in a place where scraping is legal), I generally wouldn't agree, on the basis that self-justice is something we generally agreed to avoid in order to build functional modern societies. Trying to inflict some harm on people because they collectively, through their democratically-chosen representative, made a different choice than you, as an individual, would have done, doesn't strike me as really "controversial" as I'd guess a large majority of people would count that as rather unethical.