Nubrac's ban isn't justified
Playing teemo support mid isn't griefing.
Its off-meta, but off-meta isn't griefing when he has a 50% win rate while doing it.
And riot says that off-meta isn't bannable. You can play anivia jungle if you want to, you're not gonna win many games, but you can't get banned for it.
You're just wrong if you think otherwise. Yea it's pretty troll, but anivia jungle is pretty troll too and its not bannable. Riot supports off-meta as long as you are trying to win.