Most of the time these kinds of players are the result of easy leveling through fate grinding, where they get 0 experience actually tanking, just press random buttons because "it's damage" and don't really get party wide damage to learn to heal or they are just THAT bad and got carried through the game by over geared players....

"Hi im new" is certainly no excuse for not knowing even basic tanking skills or the basic skills of whatever job they are playing... i agree with you there OP and i too am sick of this with random PUGs, i don't even do PUGs in DF anymore because this kind of experience is FAR too common :L