They should also ban creating digital art, as digital art takes less effort than paper.
Hmm I've seen someone draw/paint on both paper and an iPad. It didn't look to me that she was much faster on digital. But then it was original art not copies of something.
In much the same way, sure you could dedicate your life to learning the craft of prompting an ML model to produce unique, novel, and interesting art, but these communities are saying "we want these to be considered a different class of art" and as mostly self organizing communities they are well within their rights to do so.
But it is a lot less effort in a lot of ways. If I'm painting in Photoshop or Krita, I have layers. I can adjust blending modes. I can move them up and down. I can easily ctrl+z a mistake. I can rotate my workspace quickly and easily in ways that would be difficult with physical media. I can easily find the color I want without having to purchase more paints and blend them, or colored pencils, or whatever. I can create brushes and variations on them to match my style. I can go on with dozens of other things.
I happen to think all of that is a good thing, and don't know that comparing digital art to AI generated art is a good analogy, but digital art 100% makes many things you do in art easier.
I do think it makes logical sense to try and ban "AI" art if it is not what the community is interested in. It's likely not just about pretty images. They might value the mental process, the individual's style, progression, techniques, and yes, the effort. Someone coming in with generated images expecting to be treated the same is to me a bit like commissioning art from someone else, and then presenting that as your own. The images might be great, but it's not in the spirit of the community. There must be tons of "AI" focused communities for that.
I suppose they will eventually fail at resisting this, but that's another matter.
Secondly, it will just become more and more subtle as art softwares will subtly repackage such AI tools into their art software packaging. I am willing to bet anything Adobe is already employed an army already to figure out how to do so. How would you tackle that?