That guy is an unfortunate part of any gaming community. I have to assume they have nothing in their life that they can control except video games, so the only way they can feel good about themselves is to act like that.
Try not to let it get you down, and make it a policy not to run with people like that. If someone joins the group that you're uncomfortable with, kick them if you're in a position to, and leave if you're not. It's your gaming time, you decide who you spend it with.