Unity doesn't work by hoovering up the collected works of humanity, mixing it all up, and extruding it as a paste as a response to a sentence or two prompt (yes, image generation is more complicated to prompt but it is still roughly a paragraph of text).

Look, if you personally don't see the issue with AI, I still have a hard time believing that you haven't seen plenty of varied arguments against it. Ignoring all the varied reasons to pretend it's only some needless hand-wringing at this point just feels like bad faith.

And either way, we're talking about a tag/label. I see no issues with games having a tab/label/etc on their store page indicating the engine they're built off of. Some people don't like horror, puzzles, always online, forced PvP, or a particular art style. Some people don't like generative AI. I don't think there's a strong argument to be made that usage of generative AI should be a special case here. If no one's harassing people, I see no reason to prevent people from making informed decisions on what they purchase.

If your counterargument is that AI is just a tool, and we don't tag whether the artists used a mouse or a drawing tablet, I'd counter with this: hand drawn art is a selling point due to the increased workload to create it (and implied extra quality). Now "no generative AI" can be the same. An indicator that things were done "the hard way", with an implication (but no guarantee) of higher quality.