People who are bullies
True,two of the instances occurred when these characters were kids, and the saying goes that kids will be kids, but will they? No, not all kids are taught to make fun of and taunt their peers. A lot of children are pretty even tempered and well mannered, I know because I have not parented them, but have taught them and most of them might make out of line remarks about other kids who are different, but they do not go so far as to literally harass and bully them. Which just goes to show that the kids who do this crap eventually forget about it, but it stays with them in the back of their consciousness. Most do eventually grow up to be mature and responsible adults, but they never truly forget what they did as a kid.
"Duh. You're the idiot. Not me."