Why? If someone like something you personally don't like, or you personally can't see the appeal of it, you can't respect them?
How is your attitude different from my dad saying that rap isn't real music, or his dad saying that rock n' roll isn't real music? Or that only a degenerate would have long hair? Just more examples of people with strong personal preferences trying to turn their particular and arbitrary preferences into universal morality or intrinsic value.
In the best possible cases this just leads to intolerance and narrow-mindedness. In the worst case it leads to denigrating and dehumanizing people who don't share our values, which can lead to very very dark stuff.