I quoted some posts for an example of this... but went ahead and removed them from this comment. Decided it would be better to not point fingers but just speak generally to make my point.
There is trend in the game, that has even carried it's way onto the forums. It's very common in MMOs, so this social discord dose not even really get noticed all the time. It being so common that it just blends into the background music.
But when a group goes down, everyone want's to know who to blame for it. Which is why a lot of players are quick to point at someone else, so as not to get accused of it themselves. ---kinda like farting in the car when you were a kid. Remember the old "Who ever smelt it dealt it" ?---
I was in a group the other night that was so refreshingly different. We did very well, and only had a couple of hiccups. I forget the name of that zone, but it was in that one that takes place in a cave in the desert. After you clear each room, the portal to get into the next area, is clicking on a small pool of quicksand.
When we got to the 2nd boss which was that giant worm, the Archer dps died 2 or 3 times during the fight. After the fight was over, the healer and I both typed up a quick apology to the Archer. She apologized for not getting close enough to him in time to target and heal him before he went down. And I apologized saying that I was not sure why or even when I lost the aggro on the boss. He then told me it was not my fault. How I kept the aggro and that boss will just target random group members during the fight. Then told the healer it was not her fault either, that he mains as a Tank and he was still getting used to playing as DPS. So remember where to stand and move to get out of the way during a boss fight was something he was still getting used to.
Every pickup group is unique. When the group keeps getting killed, typically it's because some party members are refusing to alter their own play-style to fit that group. Sometimes the strongest player, can be the weakest link in the chain.