I don't like River Song. I used to (in fact, she used to be my favorite character), but after series 6, I can't believe the actions she took don't cross the Moral Event Horizon. And she got away with it! And no, don't tell me "it doesn't count" because she's in prison; that's for an entirely different reason and she's shown to break out literally any time she feels like it. Apparently disliking River (albeit mostly due to her fans and the way she was handled) is an unforgivable sin in the DW fandom.
Also, I dislike professional sports and the leg up players are given in education, as contrasted with math, science, and the arts (which tend to get cut). Still, that opinion seems to be growing in the mainstream, so I'm not sure that counts.