If you really want me to express my opinion, then fine.
Because his music is bland and untasteful for me, and because his attitude and behaviour recently has been offensive, awkward, insulting, pathetic and just plain rude.
But also, know this - I don't really care much for him. I don't want an argument over this; if you like Justin, then that's fine by me. Everyone has different tastes, everyone has different opinions. Just because our opinions clash doesn't mean one of us has to be on the wrong. I can say one of my favourite movies is 'Bridesmaids' and some people would call me names because of that; so what? I don't care what they think. And you shouldn't either.
So don't go around hating on people who dislike Justin Bieber just because they disagree with you. People will have different opinions than you. That's life.