Another problem: Most of the younger gun-grabbers have no idea what Marxism is. They've been so thoroughly indoctrinated by the public school systems thay they truly believe what they espouse is for the good of humanity. To them, we are supposed to be living in a "Democracy" rather than the Republic guaranteed by The Constitution. Arguing with them is much like arguing with a Martian... without an interpreter!
That is a problem, and I don't know how to deal with it, beyond letting them see what happens when the shooting starts.
But it's a fact that countries that allow citizen firearm ownership are virtually immune to attack. Well, unless you're attacked by crazed muzzies dead set on dying for Allah. That is problematic.