I can't agree more with you. I have seen people not trying at all, hiding behind excuses like "chill out it's a lv77 dungeon" and yet we've been here for more than 30mins because they did not bother to aoe, do their rotation or even perfrom the mecanics. I've been called an elitist because I called out someone who died on the final boss and released on purpose, and was just standing at the entrance while we were doing the hard work. It took almost 15 minutes to kill it, I was the only person actually trying to pull my weight and compensated for all their mistakes. I even had to place markers on the ground so they could at least survive what was coming (and they were not new at all, they all had some lv80 jobs already).
This was a leveling dungeon, level 77. And yet, I was called names, I was told that those persons had a life and paid bills hence I should chill out. As if all the persons who can actutally play properly were just a bunch of nerds, failure of humanity who should be grateful that those "real life workers" and "bills payers" bless them of their presence. Sure mate, I work and pay bills too, what's your point?
This is just an example, I have had tons of similar situations since I have been playing.
Fortunately, I have also had plenty of great runs, and met a lot of nice people. But all in all, we need to stop this entitled mentality and have a way to make people understand that any group content is a common effort shared among the team.