Im against limiting freedom of speech in any way or form for a couple of reasons.
One is if you censor their posts then we wont know who the genuine racists, bigots, fascists etc etc are. I think its far better for them to speak their minds then we know what kind of person they are. The term give them enough rope or keep your enemies closer comes to mind.
The other reason is once you start censoring people it is a slippery slope and you may get biased censoring. This is a problem with movies and TV as well.
Put them on ignore if you don't want to read them or make a complaint.