Interesting point. Police stations do have guns and don't get attacked. I haven’t thought of that.
“Laws that forbid the carrying of arms . . . disarm only those who are neither inclined nor determined to commit crimes . . . Such laws make things worse for the assaulted and better for the assailants; they serve rather to encourage than to prevent homicides, for an unarmed man may be attacked with greater confidence than an armed man.”
—Thomas Jefferson, quoting Cesare Beccaria in On Crimes and Punishment (1764).