There are many, many threads where this topic is discussed. Maybe read and post there about ai dislike. Or ask an AI. That was not meant ironically. They are good at summarizing such things.
My take on this is, that there is not really that much hate, but we are talking art here and using ai is not a quality feature to advertise. It does not enhance a game if you use ai assets. To the contrary. It is tolerated, just like players would tolerate stock assets. Read here for some interesting diagrams. The specific usage of ai chart in particular. https://quanticfoundry.com/2025/12/18/gen-ai/ In that survey 83% had a very negative reaction to ai artwork.
And with things that are generally disliked for various reasons, there will be extremes. That means people that are very vocal about their dislike and cite all sorts of reasons, like environmental or ethical reasons.
But as I said, we are talking art here. It is sufficient to point out that we are here for human artwork and not robot artwork. And yes, the sheer amount of ai slop is contributing to the dislike.