It has long existed as an occasional response to heat and fatigue, of course.
But as a form of youthful rebellion... well, back when youthful rebellion was truly youthful rebellion, and not simply fashion and posturing, no self-respecting rebel would be caught wearing a tie, loosened or otherwise.
Okay, maybe the rebel would wear a tie as a headband. (A particularly well regarded practice when it was an American flag necktie.)
Even if one's work place required a tie? Even bad ass rebels gots ta eat.