I personaly disagree. I think this decision is a little extreme...
I'm doing datapack, without AI. Why should I spend 2 hours of my time to make a simple cover, a bad one, wich I hate, and wich is not attractive.
I spent dozens of hours in my projects, 100% of the code is handmade, but I can't use a cover made by IA even if I did the prompt, because this little image "replaces my own creation". This sounds a bit ridiculous.
I don't like the way people use AI, not AI itself. This is a tool, like every other program you may use since your begining as creator.
Photoshop? this is cheating, from the point of view of an ancient painter. A calculator? Heretic device in 1500. Herbs medecine? Witches.
I understand your decision, and share it somehow, but I disagree with the way you apply it.
You can only spot images for now. Wich is only the visible part of the iceberg. Can you spot if AI made a resource pack? a datapack? a page description? even a map? You can't.