Bro, this is one of those times where if you have to ask why, you probably won't comprehend it even if I explain it. Either that or you're just purposely being difficult.
Dude -- the refs make bad calls against every team in every game. Yes, some calls went against the Cowboys. But they got some calls too -- for example, they got away with multiple unflagged defensive holdings that no reasonable observer could argue were not penalties.
The refs are not why the Cowboys lost. They had every opportunity to win, but just didn't make the right coaching decisions and/or plays on the field when they needed to.
Let's not be poor losers here. The Cowboys displayed the heart and mettle of a champion fighting back like they did. They have a bright future. But they also got beat fair and square, by a HoF QB at the top of his game, and a clutch kicker who came through twice. No shame in that at all. But there is shame in whining, IMO.