I'm going to let everyone gang up on my best friend
Why do you want people to gang up on them?
Because he didn't stand up for me while I was getting bullied.
I know you're mad, but you should try and protect your friends no matter what.
I don't think it's my job as his friend to defend him.
You can be the bigger person and stand up for what is right in this situation. If others see how you reacts they might think less of you.