For anyone that wasn't involved, here's situation overview:
1) in order to keep raid organized, this pug has several rules in place and if you break them, you get lootbanned. These rules are generally obvious screwups, like bombing raid on geddon, attacking wrong targets, not stacking on surgers (which is constantly reminded as a way to get lootban), etc. Typically raid reader calls out people for failing and if they still fail, they get lootbanned.
2) lootban is not for all raid, but you forfeit your next roll on an item
3) if you want to go afk, you wisper raid leader or be in a safe place/time to do so
4) This player decides to afk on a surger pack, without letting anyone know and not moving to a safe place
5) Everyone stacks on surger while this hunter obviously is standing outside and gets charged over and over
6) Raid leader calls him out multiple times and seeing that he's not responsive calls for lootban
7) After this, Hunter (player in question) says sorry for afk was on phone on TS and raid moves on (I guess he didn't hear he got lootbanned)
8) Raid reaches ragnaros and there's disusion about lootbans and this Hunter's lootban is mentioned
9) He throws a tantrum, screams like a child in TS and ninjapulls Ragnaros and leaves raid
10) Raid kills Ragnaros, we move on to Onyxia, this genius comes to TeamSpeak to verbally attack raidleader (gets banned, changes ip and comes again and gets banned second time. Don't recall if there was 3rd).
My subjective view on the matter - sometimes these decisions might seem a bit harsh, but failing to stack on surgers in this pug has always been reminded as a way to get lootban. Since this is a pug, there's no other form of punishment, no dkp to substract and so on. Frankly, this form of discipline is probably one of reasons why this pug is so succesful - super fast clear times with no wipes.
Instead of throwing a tantrum one could simply leave and not join it next week. Verbally attacking raidleader, ninjapulling and then harrasing on teamspeak multiple times is a big no-no.