I always thought that this behavior was toxic , it's the equivalent of a passive help to the enemy , the guy just go solo and refuse to listen to team util they obviously loose in 4v5
I truly believe this is no more acceptable then active feeding.
i have this behavior often , but there are no specific category for this one so i end up going for enemy help + afk +negative attitude.
but that's not what it should be.
this specific behavior occur too often imo to deserve it's very own