One of the hardest things for me in social networking/media is the need to respond to something that I see which is damaging, bigoted, a slur, sexist, etc. I am not content to sit around while people I know use language that degrades other people. I feel like if you ignore something, you condone it. But pointing it out can make me a target and get me embroiled in an ongoing shouting fest. One of the most liberating things I have discovered is that after calling someone on it, I am in no way obligated to stay in a debate with them. I don't need to defend my position or continue an argument. It really is okay to just say, "I'm not all right with this" and then never look at it again.
There's a very small and coldly logical part of me that realizes actually, it will bother them far more to be called on it and then get no response to their rebuttals. Continuing to engage doesn't help.