Why do you think people are generally pro Large Language model but anti AI art ?
In my experience with artists, they don't care about writing because everyone "can" write. It's something basic that's taught in grade school. Graduating even middle school requires you to be able to write a sentence and an essay, so it's considered trivial. (Of course, writing good
fiction is completely different from writing a good grade school essay, but they don't care about that.)
But
drawing, that's special. Not everyone can do it well, and it takes a lot of practice, and so they consider it sacred. Making writing easier doesn't matter, because it is already "easy", but making drawing easy? Now you are affecting
them. Now
their special skill is able to be accessed by anyone, and that's a threat to their social status. They don't want the average person being able to make a picture, because it takes away from them being the special ones able to do it.
This is why we saw the enormous glut of absolutely horribly written webcomics in the 2000s. Every artist thought they could also write a competent story. The art may have been passable, but the actual plot and dialogue was horrendous.
Also, as Mr. Miyagi said above, generating text is relatively common. Chatbots and the like have existed for decades, so it isn't that novel of an idea. Obviously none of those were on the same level as current things like GPT-4, but the concept has been around for many years. Generating images, though, that is new.