I think one aspect (out of many) that makes AI art so icky is the inherent insincerity of it. It imitates art that takes human artists dozens of hours to create and is appropriately appreciated by people, while itself only taking seconds to generate. AI artists want the same appreciation for their low-skill, low-effort slop as people who have honed their craft for decades and without whom their AIs wouldn't be able to function. Additionally AI art takes up so much raw space, any art platform that doesn't ban it gets absolutely flooded with low-effort assembly line garbage that often refuses to identify itself as such, hoping to trick people into thinking someone actually put work into it.

Art is not impressive if anyone can do it. A photo-realistic drawing is more impressive than a photo of the same thing, even though the latter might be "objectively" more detailed/accurate. I could create a Star Trek cartoon like that within an hour using GenAI, but creating the exact same thing by hand would take me years. AI artists however pretend like their low-effort slop has the same creative value as any hand-made art.