Some had been worried about “antifas,” the violent self-proclaimed “anti-fascists” who have physically attacked Republicans, Trump supporters, etc. elsewhere.  The antifas were notable by their absence.  I’m told one of their mottos is “Put Your Fist In A Fascist’s Face,” their definition of “fascist” being anyone they disagree with.  How ironic that they don’t understand their behavior is the very exemplar of fascism.
Perhaps they thought if they tried to “Put a Fist in the Face” of an NRA member, they might get a response of “Blast a Bullet Into a Brainless Bully’s Butt.”

Source: Massad Ayoob » Blog Archive » 2017 NRA ANNUAL MEETING: FINISHING UP

I reckon something like that went through their little brains and a modicum of self-preservation was engaged.