Actually I think everyone here agrees that the professor's response was overreacting. I think the real question should be whether this overreaction is a symptom of a larger problem as it is not strictly an isolated case. It seems that certain points of view are deemed acceptable by some in academia to silence. It also seems that some people have an irrational fear of legal firearm owners(which I think is a more likely root cause). Perhaps its hoplophobia. a fear of weapons.
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." Thomas Jefferson