If you want to skip the premise, skip to The Point
Yesterday I was doing some random dungeons for the GP. I was on my main, which can do all roles. I was a healer at the time.
Queued to a random dungeon and got Bal Sunnar.
Us supports were higher CP, while our DDs were CP200 and CP400. Nice fellas, turned out. But the tank didn't respond. No reaction. Didn't respond in group chat. Just standing there. 30k health, so probably not a real tank anyway. No idea if they even had a taunt. We wasted a couple of minutes waiting if he is going to respond or not. He didn't.
So we cleared a few trash mobs. I wrote in the chat that no worries, if the tank doesn't play I can swap to tank gear for the bosses. We were already at the bridge that leads to the house with the first boss when the tank finally wrote something. Didn't move, mind you. Just wrote a single word. "smoking" Um... ok. A bit weird to queue to a dungeon and then go for a smoke leaving the rest of us waiting for you. Especially because the queue is short for a tank.
But no movement. Nothing. Then a minute later another text. "will join at bosses" Yeah, no. What arrogance. Make us wait, then expect us to clear the path for you that you can walz in to do a bit of tanking (who am I kidding? He would have not tanked. Just parsed the boss and died on every light attack and complain in the chat "fake healer?") and then afk until the next boss?
So we voted him out and I swapped to tank gear. "Only until a real tank arrives" - spoiler: a new tank never arrived. Left a couple of heals so I can provide also healing for the DDs. Finished ez as a trio. Took a bit of time because CP in low hundreds doesn't necessarily do high dps, but we managed without wipes.
The Point
I know there's a lack of supports in this game, especially tanks. Tanks should be cherished when they decide to join with random people. But don't abuse it. Your 30k PVP build might work if you'd actually play, but don't treat other players as NPCs. If you want to be treated like a princess, play a Princess Simulator. Other players are real people.
Don't port into a dungeon and then go to have a smoke without saying anything to anyone. Of course other players are waiting, especially low CP who might really need a tank. And especially, don't then arrogantly announce that you only join at boss fights. It's a group dungeon, not a "carry a self-proclaimed VIP" dungeon.