The benefits of being bad?

As an observer, I can only be horrified when I hear someone say stupid and cruel things. I don't think I'm better than others because of my views, not at all, but I'm amazed at how half my acquaintances prioritize their values.

Today in literature class, after hearing that a character ripped out his own heart to light the way for others, my classmate said to her friend, "What kind of idiot is he?" and it's not the only time something like this has happened. She and some others behave rudely to those outside their group. What I don't understand is: what advantage does this have? Does it make them feel better? Does it make them seem confident and courageous?

I go to great lengths to keep my cruel and harmful thoughts from being revealed because I hate them myself. But why would anyone deliberately unleash theirs on others like this? Is this who these people really are, or is it just maximalism? I can only hope it's the latter.