Then why do Spotify and Netflix et al persist in identifying artists and songs I've heard of (because of obvious similarities to stuff I like) but have actively ignored (because of any of a number of reasons that don't boil down well into an algorithm), over and over and over again?

I still don't want to watch The Office, Netflix. I won't in another six months, either.

But I could tell a person why not, and they could factor that into their recommendations. It's like the difference between trusting Waze and trusting a local that says "even though the app says go another half mile then turn right, turning right here is way easier, since if you wait you'll have to then quickly make your way across three lanes of traffic in a hundred yards to make your left, and making the right here gives you more time to get over."