A hippie rejects established culture, much like a hipster, but in favor of a slightly different alternative culture. Hippies like protests and anything "cooperative". They were least partially responsible for the 1968 protests, although the occasion must have shocked their non-militant sensibilities.
Hippies often follow the leftist party line on issues like the Manhattanville expansion but are left confused and uninformed when challenged in serious debate.
Hippies you might meet at Columbia are mostly a special subclass called "hippie-come-latelys" or "trust fund hippies" or "trustifaritans". Tell them to put down the frisbee and get out of their tent. Counterculture posing isn't political, and slumming for fun is hypocritical.