You invoke gatekeeping and the no-true-scotsman fallacy. Fair enough. I might add "Dylan goes electric" to the pile of examples.
However, look at this other comment: https://news.ycombinator.com/item?id=48099547
There, patterns of electrical signals are said to be good, and not bad, but at the same time "morality" gets dismissed. But ideas of good and bad are morality!
Note that moral ideas don't have to be correct. "I should burgle a house" is a moral idea, an idea in the domain of morality. 1920s disapproval of the seductive decadent jungle rhythms of jazz was moral (I guess we say "moralistic" to indicate that we don't agree). The opposite attitude, praising jazz, is also moral. Treating Dylan as a traitor for going electric was moral, and attending the metal love-in that was Ozzy's farewell concert was also moral.
Then, a couple of posts up the thread from you, there's an imagined scene of people "vibing" to music at a party where everything is AI made. This sounds disgusting, somewhere between vaping and using a vibrator, and so I think I have to grudgingly give it my full approval. These imaginary young people are enjoying the vibe that they have vaguely selected. Maybe they had some input about the genre, maybe implicitly. They're choosing not to turn it off, anyway, because they like it, they think the vibe is good.
You imply that everybody saying "It's not real music" is wrong. OK, kind of, but they're not completely wrong. It doesn't follow that just because of our long history of snobbery, therefore everything is real music. The snobs are doing gatekeeping, but they're also doing discernment, and participating in the kind of moral ideas that music and art is made of. It's such a pain to define art that I'm liable to be downvoted for trying: some people are certain that relativism is the way forward, and that it's a brilliant insight to throw our hands in the air and give up. You're quite right that it has to encompass lots of different things, and no one defining feature will withstand counterexamples, but it can still be defined in a vague way as a collection of optional qualities, under which we could say that an instruction manual is not really art, but arguably artistic or artfully made.
So, I'm not judging the AI music as art or not-art right now, but I'm saying that it's amenable to so being judged. Anybody claiming that it's good music is admitting the possibility that it might be bad music, and this is a moral matter, about the value of feelings, meanings, and affections. That even applies to good or bad elevator music, it's trivial background sound, but approval or disapproval of it is moral. This is not about its worth as patterns of signals, because that's reductive. Those patterns mean things, or matter to us in ways that we have preferences about, which are value judgments.