Well a ban seems too strict dont you think? I think it's better to encourage human art rather than an immediate ban. Honestly I wouldn't care since I like drawing. But yh I get what you mean with AI slop, I dont like it either.
Maybe a disclosure or tag to your game if you use generative AI might work I guess
Itch already has a disclosure in their page settings.So games should already be tagged to show whether they used AI or not.