Thought experiment:
You want to paint a picture of an elephant, but there are no elephants where you live and you can’t remember what they look like. You do a Google image search and look at a whole load of pictures of elephants; some of these images are public domain, others are subject to copyright, some of them are just thumbnails of an image you would need to pay for if you wanted it full size or if you wanted to own a hard copy, some of them are subject to other restrictions I can’t think of right now, but all of them pass before your eyes.
You didn’t seek or require permission to put any of those images into your brain, via your eyes, but in any case you spend a while looking at and studying various pictures of elephants, understanding what they look like, how they work, etc.
Then you shut down your computer and get out your art materials. You paint a lovely picture of an elephant, that undoubtedly was derived from, or inspired by, one or more of the images that passed before you in the Google image search.
This happens all the time and I don’t think anyone has a problem with it. Even if you also studied the paintings of Van Gogh and ended up attempting to paint your own picture of an elephant, in the style of Van Gogh, I don’t think anyone has a problem with it. Try to sell it or otherwise pass it off as an authentic Van Gogh painting and sure, that’s a problem.
And, although there are differences between the human eyes and brain vs the inner workings of an AI based image generation program, the principle is rather similar; it looks at a bunch of stuff, learns about it, formulates something equivalent to an understanding of the material and styles, then generates images that are derived not from the source material itself, but from what it has learned about that source material.
The key difference between a machine doing this vs a human doing it is that the machine can do it far more rapidly or prolifically and in some cases, can produce results that, whilst they are not fine art, are above the level of the average self-trained human, and potentially it can memorise details etc more reliably than a human.
The problem (and I agree it’s a problem) appears to be not what they’re doing, but that they can do it wholesale with great ease.