Anonymity doesn’t necessarily mean namelessness - it means being a voice in a crowd, it means being seemingly removed enough from your target that you, personally, won’t be the target of retribution. It hearkens back to really primal primate behaviour.

Group dynamics are crazy - you can use them to get people who might be drinking buddies to instead get into tin cans and try to murder each other, because you’re using the ultimate anonymity of a battlefield to let slip the dogs of war.