Stop making excuses. AI training on copyrighted works is straight wrong no matter how much you don't want it to be.
All of my internet comments are copyrighted btw, but I do offer a license of $1b usd/year for using them in a model if you'd like.
I don't think anyone's saying that the output of the model should be subject to more lenient copyright standards than human creations. If you're selling a remix with substantial similarity to an existing song and it fails the fair use factors, then it'd already be infringement regardless of whether you made it with AI or by hand.
The question is: what about the songs that you've listened to, and potentially influenced you, but don't have substantial similarity to the remix? Do you also owe royalties on all of those? For humans the answer is no, but the law doesn't necessarily have to treat AI the same way.