The horse**** calls didn't all go the Cowboys way. Clinton Portis got two no-calls on the same play in the 3rd quarter. One when he trapped a pass but was credited with catching it, and the other when he was allowed to advance the ball for a first down after he was touched on the ground. That kept a late Redskins drive alive and made the score a lot closer than it should have been.
The officiating was terrible and hurt both teams in that game, but then again the NFL officiating is terrible in just about every game and has been so for years.
You are right, but the difference is that both of the Portis non-calls (trapping the ball and then running after having been touched and putting his knee down) were reviewable, but Parcells chose not to challenge them. The pass interference calls were not subject to review.