In what respect does this hold true?
If I queue as a tank in Quick Play about 90% of my games are on defense. It isn’t luck of the draw. It isn’t the matchmaker doing its job and placing me with others of the same MMR. Its my win rate of 58% that makes that happen. Attack teams have a higher percentage, by the numbers, to win games. This was easy to see when the game came out and you could see hat statistic on Overbuff and MasterOverwatch. Private profiles made that skew, and Blizzard removed win rate for a while as well.
I am aware competitive doesn’t really have that problem, but Blizzard’s matchmaker, in some game modes, most certainly takes win rate into consideration.