You can't listen to MM complaints for many reasons. Among them is the following:
If it's working perfectly and you're playing at your typical skill level, then you should lose about 50% of your games. So if each match is independent, when you queue up your success is kind of like flipping a coin.
Fun fact: Arbitrarily long runs of consecutive heads and tails appear with positive probabilities in long coin tossing games. I forget the exact details, but basically it is not impossible (nor even really that uncommon) to see, say, a string of 100 consecutive heads if you toss a coin for a long time. Computing this probability is one of those fun first-week-of-class problems in any graduate probability course.
The quote the OP references could be (approximately) the above phenomenon.
Besides that, sometimes you just have a bad day. [Edited for conciseness].
Moreover, MWO is the kind of game where if a few otherwise good players make a few bad decisions, a lot of bad can suddenly happen. Imagine a game of chess where the pieces control themselves and your Queen decides it's time to try a flanking maneuver and gets taken immediately by a pawn. Well, your game just got a lot harder, didn't it?
The list of conceivable explanations for observed match maker behavior goes on. Yet another that comes to mind is that even if a game ends 12-5, for example, it might be that the total health of the team with 7 survivors is something like 45%. Yea there are 7 of them alive, but they're 1 medium laser to the chest away from death. This would explain why 12-11 games are so rare. When both teams are down to 20% health, all it takes is one double-ER-large-laser Raven on a hill to wipe out 3 guys in 3 volleys.
Edited by Water Bear, 11 March 2015 - 12:33 PM.