Again, I have to ask, WHY would the air bags deploy when there was no front end damage?

Your head rests keep you from getting "whip lash" in a rear end accident.

In 1965, my Mother and Father were driving home and had just crested a hill at around 35 mph, when a few moments later, a guy driving a 1962 Buick Wildcat convertible doing 100 mph crested the same hill and collided with them without ever hitting his brakes.
His passengers told Police he had been drinking, and he told them he could reach 100 mph by the top of the hill, and that's exactly what he did.
My Dads "Demo" was repaired, and sold as new, but the Buick was totaled.
Fortunately my Parents walked away with only sore necks and shoulders for a week or two