Perhaps knowing a human with talent worked on it, putting some small part of themselves and their lived experience into the music has value to them? If so, then their actions make complete sense.

Human created music might have value to them, but it doesn't mean that the AI song was valueless. They admit they enjoyed it. So it doesn't make sense in terms of it not having value.

I wouldn't say it's asinine though. People reject creative output out of personal protest against the creator. Someone might love a movie only to refuse to ever watch it again because they found out the director was accused of something horrible.

Some people just don't want to support anything to do with AI. Although in this case the OP admits to also using AI directly so there's some inconsistency there, which is consistent with the state of confusion and uncertainty OP is expressing.