They aren't, or they shouldn't be, but that's the point of the parent's comment.
Look at the videos flagged by youtube or copyright trolls, a lot of them are not actual copyright violations, but they are flagged anyway by the algorithm and removed or demonetized. And it takes a lot of work to fight those claims.
No, that doesn’t seem to be the point of the parent’s comment. That comment is treating those activities like copyright violations when they’re not. Why would the parent imagine an omniscient copyright bot that is probably wrong?
Me singing happy birthday at home or painting a picture for myself to relax is already demonetized. There doesn’t need to be an omniscient (and wrong) copyright bot to do that.
Look at the videos flagged by youtube or copyright trolls, a lot of them are not actual copyright violations, but they are flagged anyway by the algorithm and removed or demonetized. And it takes a lot of work to fight those claims.