No, I don't think most people are really against AI Gen works "on principle". Or at least not in any interpretation of "on principle" that would allow for you to be dismissive of complaints in this way.
I think principles are important. Especially when it comes to art, principle might be all we have. Going back to the crypto example, NFTs were art that real people had made. In some cases, very good art. People railed against NFTs despite the quality of the art. That is being against something on-principle. Comparatively, if my local grocery chains were owned by neonazis, I'd have a much harder time of standing on principle, giving that doing so may have a negative impact on my ability to survive and prosper.
AI Gen works, on the other hand, most often do not come with readily available marking that it is AI Gen. What people are complaining about is the lack of quality in the work. If they accuse a poorly human-written article of being AI Gen, that's just a mistake. But the general case is a legitimate evaluation of the quality of the material and the conditions under which it was made and presented.
In my own case, while I certainly have plenty of "principled" reasons to dislike AI Gen works, I also dislike it because it's just garbage. Oh yeah, sure, it's impressive that a computer can spit out reasonable content at all. It would equally be impressive for a chimpanzee to start talking in full sentences. That doesn't mean I'm going to start going to the chimpanzee for dissertations on the human condition.