Every defensive lineman in the country is taught to get to the QB, and if you can't get to the QB, get your hands up and mirror the QB's arm.

The vast majority of batted balls come on quick passes where the target is near the line of scrimmage and over the middle. It's simple geometry that those passes will get batted down at a higher rate, regardless of the QB's arm angle. Offensive linemen are taught to cut out the defender's legs so they can't get their arms up - so at that point it becomes a matter of whether the defensive lineman does his job better than the offensive lineman. It isn't about the QB's arm angle.

Utah batted a lot of balls against BYU because a) they were abusing our offensive line and b) BYU resorted to calling a lot of quick passes in that game because our offensive line was getting abused.

I'm willing to bet that if you look at BYU's offensive and defensive balls batted at the line of scrimmage, they are within a few of each other.