I know, people can be so incredibly insensitive. Been there, done that. From classmates/co-workers to supposedly "close friends", eveyone has the ability to inflict huge amounts of emotional pain to each other. I've been both a victim and a perpetrator, we all are to some degree. I too have been told very offensive things and names in the past (e.g. I've been called an "AIDS carrier" due to my acne issues), I've cried a lot, my self-esteem has been annihilated and I have turned out broken and depressed as a result.
However, I've also been a perpetrator, since I have hurt others. For instance, one particular case I deeply regret is about an ex friend of mine who has slightly below average intelligence. He wasn't mean or cruel to us by any means; in fact, he was probably one of the most harmless people in the whole group of friends. Yet, due to his cognitive limitations, we (the rest of the group) deemed it okay to mock him. We were the heartless ones, not him. He definitely didn't deserve such awful and nasty treatment, and I would have liked the opportunity to let him know just how sorry I am.