I don't know if I've been massively unlucky or something, but I just seem to find these people quite frequently in WoW.. And my experience is completely the opposite. The loudest people seem to be the ones who never learn, because it's someone else's fault that they fucked up.
I don't mind new players that eventually get carried in M+. After a few weeks we have enough gear to 4 man 15s within the timer.
But it's not like I think this will change anything. They'd have to enforce it, but they rely solely on reporting to sort out these issues.