That footage is from the time when Bradshaw was taking his concussions. The average NFL QB holds on to the ball for just under 2.5 seconds. NFL football is violent because the players are big and fast and the game as a whole moves fast. It’s a matter of simple math, you have guys in excess of 200 pounds moving around so fast that the QB has to get rid of the ball in under 2.5 seconds impacts are going to involve a lot of force, force causes injuries.
QBs getting hit blindside by guys significantly heavier then themselves coming at full tilt while they (the QBs) hold the ball waiting for somebody to clear zones.
Receivers getting hit by more than one person as they concentrate on catches in zone coverage.
Runners getting hit by more than one person at points of attack, in part at least because QBs don't contribute anything to a running play in the pro system and it's 10 men versus eleven.
Again the wishbone teams didn't have any of that and the Naval Academy's offense doesn't experience any of that.