ETA first off you laughed at your friend, I get it friends jokes , harsher jokes can be made easier the closer friends are. Could have simply smirked to prevent others hearing and laughing. Now they know he’s kahoot name and friend feel pressure to guess right. Classmate sucks cause they should realize everyone can make mistakes. Teacher is doing good job trying to prevent bullying. Though a warning and asking your friend if he’s okay should have been step one. The confrontation from your part was bad and could have expressed more emotions. Everyone sucks to only blame you when they were to blame to. When saying everyone I mean all except friend who’s the victim