I'd rather it fill my feed with stuff that I actually watch than with random crap that I don't care for. Plus, all you have to do is watch a video, and YouTube will do that. If I watch one or two videos about alligators, YouTube will seem convinced that that's the only thing I'm interested in.
To be mean sometimes, I'll subscribe to a bunch of polka channels on my wife's TV, and let some of them play while she's off somewhere. It will take a few days before YouTube finally gives up on feeding her polka. Once, I changed her default language to Swedish, but that's another topic.