Correct both are at fault.
But blindly blaming PL when its not the problem is rather pointless. I know people who PL'd who are very good at that jobs. At the same time I know people who didn't PL who are horrible. When you go with a PUG there is always a chance that you will get at least 1 bad person. Try to teach them. If the refuse to learn. You've done what you can, kick/blist and leave them be. That's all you need to do. You don't need to blame PL, Obama, or anyone else but the player for not learning their role.