I rarely unfriend ppl but I like keeping a variety of opinions
  on hand for any subject that interests me. That's my thing: I've
  got a bit of a sociological/anthropological view of humanity.
  But I wouldn't ever ask anyone else to do it as it requires
  extreme suspension of one's own opinions about many hot button
  items. A few friends are an extreme test of that resolve but
  that's why I keep them. I regularly have friends block other
  friends and I've had a few block me for even KEEPING such
  friends. But again, that's my thing. It's my hobby. Everybody's
  got different foci.