No, the problem is stolen art. AI art is derived from it's inputs which, at the moment, are almost always used without permission.

Additionally, AI art sometimes outputs essentially copy/pasted fragments of its inputs. This means the user may end up with something that basically has stolen art with no alterations from the original. I believe this has already happened with an AI-generates book cover. It has an astronaut in some weird landscape and the astronaut was an unaltered crop of one of the AI's inputs.

It's theft. It's unethical for many, many uses.

It's fun for casual use for sure, though.

Now, if someone were to create their own generator and fill it only with their own original creations, then there's really no problem.

But that's not how things are.