It sucks you've had bad experiences or been bullied. I don't want to bum you out but you will meet these people in varying capacities throughout your life. And unfortunately the best advice I can give you: avoid them. These people won't change because of something you say or do. Simply put they're either born or programmed to be knobs. So just leave the chat group, fire team, whatever it is you're doing. Don't just tolerate it. Friend the people who you like and play with them.