What did they learn though? They can't possibly know
why I'm not interested in that tweet, because there's just not enough information. So all they'll do is stop showing me tweets from that one person. No way to express "yeah I'm interested in his tweets about music, not gardening." The problem is that mostly following people means that you can't teach the algorithm about your particular interests.
Topics are better, but there doesn't seem to be a way to make sure your tweet ends up in a particular topic. Again, you have to pray to The Algorithm that it will label tweets correctly. And if your particular interest isn't a Topic, you're out of luck.