Back in the late 70s, it took a special kind of courage to wear a shirt like that. The cultural atmosphere was very different. It was still considered fashionable to spit at veterans who'd come home from 'Nam and call them "war-criminals". Popular celebrities were PROUD they collaborated with the enemy. Guns (and not the criminals using them) were the entire source of "the crime problem." Pop-psychiatry was in its first full blossom and people like Marty's dad were automatically branded as psychotics who simply HAD to be overcompesating for under-developed genitalia.

Their family was very "progressive" for the time and far moreso than the more typical "progressives" of the time would have ever liked.