Personally I dont hate someone, because he produces music that I dont like. So I dont feel myself as king of the world and others to be my slaves, so why should I be angry at someone, that produces music he likes, instead of music I like. If I was musician I also would think it to be more important, that I like my music myself.
And not everyone can have my music taste, but thats no cause for anyone to hate me.
So all these "Justin Timberlain or Bieber (or whatever) shall diediedie and all fans of them are dumbdumbdumb..." comments on youtube, I really hate. I mean the comment page of an Iron Maiden song is to tell each other, what you think about that Iron Maiden song, and not to tell each other your oppinion about an song or artist that isnt linked in any way to the song I am listening right now. I mean I cant see an connection between Justin Bieber and Bands that perform european orchestral speed metal, so why are 50% of the comments about him or other artists in this way? If I listen to Blind Guardian, I wanna read about blind guardian, if I listen to Rhapsody, I wanna read about Rhapsody and not some Kindergarten rhymes about someone else that have been posted on thousand other non fitting videos anyway. I mean people complain about singers and their missing creativity in the eyes of that posters, by posting noncreative rhymes that already have been posted 1.000.000. Thats simple spam for me and it sucks.
If I boycott singers or artists, then because of their personal oppinion. As example Chris Brown because of beating his girlfriend which is a Nogo, Rihanna because of being a wrong role model for woman when she keeps on a relationship with a partner that has beaten her once which is also a Nogo as well, general all kinds of groups that are trying to enlarge hate, discriminatory or prejudices in their listeners, or artists that promote groups that are based on deceiving and cheating like Scientology (Becks, ...) I also do not like artists that were parts of successful bands and groups and try to focus the efforts of their success as a band or a group on their own single person. So as example Prince normally produces and creates his songs alone and used studio musicians for recording and concerts. So its ok for me, when he is talking about his success. But these typical frontsingers of a band, that are part of a group that is based on the gathered creativity of the group, who think its everything about them and that parts from their groups and tell everyone how useless these others were and that he "is the band".... Sorry. So the instrumental part is, depending on the song, very important for me, so singing is just an instrument for me as are the others.
But I dont hate them in the way that I want to harm them, I simply dont listen to them or their music. (Or their films if they are main actors, when its about to scientology. Sorry Tom Cruise and "Fresh Prince" whose name I dont remember. ^^ The only exception is Pulp Fiction with John Travolta. The film is to good, so even John Travolta and Scientology cant ruin it. ^^)
I also dont agree with that "This and that is no music or is all the same." stuff. If you are not into a kind of music, then differences that can be very important, wont be obvious for you, because music has many layers. If you are not ordinary listening to a kind of music, you will only hear the upper layers. So as example, we were invited to a friend that is more into some kind of Techno. (I think he dont call it like that. ^^) So normally we are not into that kind of music, so he explained us, when they changed the music, so some songs were called "Goa", others "acid", others "trance", "dreamtrance"... and knows hell what. So I really couldnt hear that differences, so some songs were nice, some not so nice, after this party I only can say that songs that are called to be "Goa" have a higher chance, that I like them, so it seems to have more sounds for chilling, but if I listened to them I couldnt separate which style this and that song was. So for me its everything somehow "some kind of electronic music".
On the other side, I like listening to very different styles of metals. I prefer songs that are fast, powerful, and full of different harmonies that match together, but there are some slow songs as well I like and so on. If I hear a song, because of hearing these music so often its normal for me to hear not only the outer layers, but to dip into it and hear the deeper hidden layers as well. One day I talked with my sister about music and she told me that she couldnt separate or hear a difference between all those styles, because its everything somehow "some kind of music with guitars, a drum, and someone screaming". XD Which remembered me of the situation when I thought about Techno and all the separate groups, I couldnt separate as well, but because of not being used to it it was simply "some kind of electronic music".
So from my point, I dont judge a music style, that I am not used listening to it. So I dont like rap as example, simply because I miss the singing, and the additional harmonies. But that doesnt mean its bad, or that it wouldnt be music. Its simply music, I am not used to, so I am not able to hear the deeper layers of it. I see no use in judging a music, I cannot even listen completely.