I would hesitate to say it's very, very bad. I don't filter people on Facebook only because I disagree with them; I filter people on Facebook because, at one point, I really enjoyed the company of that person and their current tirade of hating (the police/minorities/the west/the east/obama/republicans/etc) stands to slightly jade our friendship. Anyone who can actively filter ALL opinions they disagree with is either delusional, locked in a cabin in the woods or much more active at filtering than I am.