There is some music that I don't enjoy listening to on a regular basis and that's OK. I believe that music has the power to be diverse enough to make everyone happy.(except for people who literally don't have the capacity to perceive it. See http://en.m.wikipedia.org/wiki/Amusia to learn more about this interesting phenomenon) A deaf friend told me that even those who cant hear (even from birth) have an understanding of music and can appreciate it. Learning that blew me away!
Just because I personally don't like a song or a particular style doesn't mean that there isn't a person somewhere that absolutely loves it. Maybe that song or style got them through a difficult period in their life. Maybe it helped them to become a better person. Maybe it even saved their life. Music is far too diverse to force judgements on people for what they listen to. Even songs that I have filed into the "terrible" file I still catch myself tapping my toes or nodding my head to under the right circumstances.
Music is one of the most beautiful things humans have created. It crosses all manners of societal barriers while at the same time constantly evolving. Sure, some of it ends up cliche and derivative but who are we to judge a thing that has such a capacity for bringing joy? Next time you catch yourself saying "this sounds like crap" try finding things to like about it. You might discover a new love or at least a better understanding of how some people tick. Don't judge a person by the music they like instead be happy that they can enjoy music and be thankful that you can enjoy music too.