How can knife dmg be a thing?



how can knife dmg be a thing if u dont allow friendly dmg from weapons?
i just hit a 38k game in a 14/16 match… we would easily have won this if one of my troll mates (13/27) wouldnt have killed me twice with the knife-.-

thats just a joke… he didnt even get kicked automatically and we could not kick him because he had a premade… thats just destroying games…