How "normal" is it for someone to delete you from their facebook account after you disagreed with their view?

The post had to do with a girlfriend who made comments about the health care system and incapable doctors in the US on a mutual friend's wall. I am in the medical field and know exactly how grueling becoming a doctor is. Dated one for many years. My girlfriend tried getting through community college and lasted one semester. She is in her mid-30's living at home, supported by parents and any man who wishes to contribute to her woredrobe. I think I just answered my own question. She is not a friend and not worth the few sentences I just wrote.