We can't forget our roots. But man, it was a different world back then.
Daredevils wanted to fly so bad, they were willing to overlook (?) the bleak success rate that hang glider pilots had in the early 70's. Things got better as equipment, instruction, and knowledge improved.
Either way, hang gliding was cool for some of the same obvious reasons as today: it was about living life to the fullest and truly experiencing the forces of nature.