When judging art, like when judging wine, there is very little objectivity: people have some expectations and preconcepts about what is good and what is bad and they emit their judgement mostly based on their preconcepts. In this case they have been "primed" (this is a real psychology concept) that it was AI and they invented a lot of reasons to explain why that was bad AI slop, but that happened just because they where "primed" on AI. If the post was about a lost, wonderful Monet, found for the first time the comments would have been about how typical Monet it was and how beautiful the choice of colors and the water reflects or whatever.

This is also seen when blind-tasting wines when prestigious "grands crus" are classed as bad whereas humble, mostly unknown, wines gets great appreciations. When people say that a wine is "great" or "extraordinary" is mostly because they have been primed to think it must be extraordinary, because of the name, the presentation, the prestige etc.

This problem is always true in the domains like art and philosophy where there is no ground truth and everyone can say very much what they want and it can be never be proved wrong neither right. Actually, in philosophy, all the branches that developed to be grounded on facts and ground truth have been given a different name and separated from philosophy so what remains in philosophy is just the empty words.

People are much more humble when they are asked about an hard-science question or judgement.

I am also having fun about all the hate about AI that people express, this is almost comical. You can almost literally see their little ego that feels menaced by the AI and they react based on fear and anger. Of course this doesn't mean there aren't real problems about AI use but the way people react irrationally is just fun to observe.