I'm a pretty troutty facebook friend. If someone posts something with a conflicting view to mine that is explained in absolute ignorance and general horribleness, I will comment on it. I know that it's asking for trouble, but Idgaf. Many people have done the same to me. If someone's responses bother you on facebook, it's probably best to remove them or hide your posts from them trather than trusting that they'll stick to only polite comments.