I think maybe you should agree to disagree and find other things that you have common ground on, but purposely disliking someone because they like pop music or rock music or whatever is very ignorant!
Yes, if you are solely disliking because of their taste in music then it seems very superficial and you will dislike a lot of people in the world for no good reason. None of us in the world have someone out there that likes everything that we like and thats is why we are individuals and what makes us all special. If someone's music was preaching hate and killing and violence then I think you could dislike them and disagree with them but no music specifically gets anyone to do anything they don't want to do.
You cannot hate someone based on the difference in taste of music. That is just the silliest thing I have ever heard. Imagine if someone disliked you because of the music you liked and would not talk to you, and imagine you really found them attractive. It would restrict you completely from making different friends and being able to expand your sociability. Just because you do not like the same music does not mean you may not share other things in common for example movies and football teams.
I think its absolutely rediculous not to like somebody because of their different tastes in not just music but everything. How can children possibly learn who to like and trust if their parents were so opinionated as to not liking certain people because of their different attitudes towards things. It is because of peoples different likes and dislikes of things that the world becomes a much more interesting place to be in.
if you instantly dislike someone for not having the same taste in music as you, then this is not good news for you. Your dislike of that person limits you to making new friends and you lessen the parimeters. Different folks have different tastes in their musical choices but it doesnt mean that they are dim, numpties, stupid or tasteless. Open your mind and your heart to the person themselves and you will find that you share many other things and the music is only a dot on the 'friendship' scale. I have many friends who love opera whereas I love jazz but that doesnt stop me from being friends with them.