Just a few people now and then butting in asking about evolution or religion in math class. .A bit disruptive but no more so than the anti-Vietnam-War groups did when I was in grad school. I would just point out that a math class was not the place for such discussions. I think these guys were just disruptive in general re everything.
Much disruption consisted in asking the same question over and over (different questions, some even about mathematics.)
Actually, I come from a long line of anti-disruptors. My father once related how he accidentally thwarted a plot to end the Vietnam War by blowing up the library at Stony Brook. Hopefully it was merely a coincidence that, a few years later, what was to become his office at the University of Wisconsin was heavily damaged a few weeks before he arrived, when someone else tried to blow up the Army Math building. Or maybe it wasn't a coincidence, and being around various math departments while he was there was a particularly hazardous enterprise for some reason.