In response to the “everybody should be armed” argument, people should simply ask the gun activist whether or not they support Iran getting a nuclear weapon. By the logic that the gun activist applies, everybody is safer when everybody is armed, and this would translate to support for Iranian weapons; in reality, these people almost always say that Iran isn’t a rational actor and that giving them a nuke endangers everybody around them. When they say this, you should simply tell them that not every gun owner is rational and that unrestricted gun ownership is the micro-equivalent to letting every country have nukes.