I personally don't make these groups... I mostly keep yo my group of friends (best advice ever).

But... go to 24 man content and watch as 80% of the DPS fail to out damage a tank.

Then go do an expert and watch a healer stay in cleric stance while everyone else dies.

Take a trip through the MSQ where a tank in 120+ in tank stance loses aggro to an i90 black mage.

This could have something to do with everyone's attitude towards everyone else.

Or they just don't care and are looking for the next carry.