There's nothing wrong with liking or disliking certain bands, even if its the same. I'm not a huge fan of Kiss other than a couple of songs, but that doesn't mean I don't respect their business philosophy. It's when people ignore their importance in music history, makes them ignorant tools. You may not like Black Sabbath, but to say they were not important is idiotic.
I strongly dislike Led Zeppelin. I don't discourage the fact that they have released great albums in music history, I just don't find whats so good about them that everyone raves about.