Why not do what people have always done? If there isn't a word for it in English, create one. If enough people use it, it'll be in the dictionary before long.

I suggest: odicant n. a song of hate; odicantor n. a singer of songs of hate or a mindless idiot who lacks the maturity to realise there is always an alternative perspective.

(From the Latin: hate = odi, song = canticum)

I'm sure the forum can come up with more suggestions.

Just a thought,
Harry