I know for a fact that the widely used term "trash tier" is ban-able in forums.
I suppose the words that SE wanted me to use to describe the worst of the worst players is "players that are a tiny bit less skilled than the current top rated PvP players".

Yesterday was doing roulette and got Aurum Vale, the healer had barely any time to react since the tank was getting destroyed even by single groups.
So the healer asked "Why is the tank dying so fast?".
No-one replied. Cause if i said "Check his ilvl 20/30 gear" it'll be a guarantee warning for "harassment" at the very least if i got reported by said "tank".

At least its good to know that if i ever get perma-banned for being so "unbelievably offensive" to others there's a game out there that i can join and dont feel like the forums/game is under martial law.