Most of us in that period did our duty and served - - it was a different world.
It must have been.
But I would guess that the people coming of age in 1956 grew up admiring the US military in a formative period of their lives - their childhoods were spent with the US on a war footing (rationing, etc.) and it was a commonly observed phenomenon that many graduates went to college only after they served in the military. Also, it was peacetime.
Many of those coming of age in 1966 remembered only postwar prosperity and thought they were entitled to a college education and the good life - the notion of "the man" snatching them off campus and packing them off to an hionest-to-goodness shooting war was almost bound to provoke the reaction it did.