I think, at least for me, it's that people can listen to different things. I agree with what he said about music being music, but I think people should dislike a group for more reasons than their genre, if that makes any sense. It annoys me when people are like "X band really sucks because they play this." For example, I'm not a huge fan of bands like arcade fire, but I can appreciate the suburbs.
OF course people can listen to different things, I just don't see how artist and image comes into play when deciding you like an artist. I'm a huge fan of Bayside and Every Time I Die, but I like them for very different reasons. Does that devalue my appreciation for them?