They don’t learn anything from whining. Maybe help new tanks out instead of throwing a tantrum? If it’s a +15 and the tank has never done a dungeon, that might be a bit of an expectation since at that point you should have an idea of what you are doing, but in low keys, a lot of people are learning.
No one rages more than DPS who can’t progress out of iO hell. You don’t see toxicity in 15’s, it’s always lower keys with arguably bad players taking their mistakes or lack of skill out on tanks/healers.