Some players need to chill

[Appleboops]

I was playing random DPS in a level dungeon couple days ago, we started and immediately after the first pull the Healer said something along the lines of "Messy pull, no mitigation, I'm out" and quit out O.o
The amusing part was the pull was fine and didn't need mitigation, no one died, I couldn't even see what they were complaining about

Anyway that's one single experience out of dozens of different roulettes and dungeon runs, so it needs to be taken in perspective. There are always going to be those types, but I wouldn't say it's "the community"

[Absurdity]

I was playing random DPS in a level dungeon couple days ago, we started and immediately after the first pull the Healer said something along the lines of "Messy pull, no mitigation, I'm out" and quit out O.o
The amusing part was the pull was fine and didn't need mitigation, no one died, I couldn't even see what they were complaining about

Anyway that's one single experience out of dozens of different roulettes and dungeon runs, so it needs to be taken in perspective. There are always going to be those types, but I wouldn't say it's "the community"

It's also entirely possible that nobody died because the healer blew every cooldown they had just to keep the tank standing.

Now obviously I don't know what exactly happened but the only pull that "doesn't need mitigation" is a single pull and even that is debatable.

For everything else a tank should have a list of cooldowns to cycle through, starting with heavier mitigation since most enemies are still alive and transitioning to weaker mitigation as they die, while also keeping in mind what mitigation they will need for the next pull.
The tank's job isn't just to stand there and get hit, but to smooth out the damage curve so the healer doesn't get a heart attack from sudden damage spikes.

If it was the case of the tank doing a full pull and then not using anything I can understand just not wanting to deal with the tank's health bar doing it's best yo-yo impression.

As for the messy part, all I can really think of is either the tank not picking up enemies properly, you occasionally get one that single-target attacks when there are 4+ enemies.
Or weird movement like pulling a pack, stopping in the middle of the pull and then randomly starting to run again. All that does is pull mobs out of AoEs and the range of the DPS, making them unable to attack and waste their damage buffs.

[Canadane]

While I don't disagree people need to generally chill out, but you've not actually explained the situation in which this person was complaining about. Without details, for all we know this person could be entirely correct.