Lol a bit cruel there don't you think, you not only saying they're retarded but to also have massive guts to say they should stay away from the MP entirely.
Then again I'm way too laid back and not really caring as much if I win or even lose despite, if the case was because poor team performance, or of poor skill level not suited for the difficulty.
Indeed, it's the same in every multiplayer game, some people are simply better at doing things than others be it due to knowledge, preparation, reaction time or the ability to predict how the game AI will behave in different situations.
Of course it's annoying to play with obvious leeches or people that have no idea what they are doing (which only makes thing harder than needed for those that take it seriously), but I don't mind playing with less experienced players at all as long as they at least make an honest attempt at contributing to the team effort.
Pugs will always be pugs in all games, sometimes you get to play with great players that make the experience so much more enjoyable and sometimes with people that make you quit.
Pugging is pretty much like buying packs in the RNG store, sometimes you get lucky and sometimes the PUG is like getting a double Cryo IV from the hard earned 99k pack.