You can't cry "fire" in a crowded theater. You can't print slander. Well, you can, there are just consequences for those actions. Consequences which also regulate the use of firearms, you can't fire a gun in theater, and you can't shoot at someone you hate.
but you can't limit the access to them in any way to citizens in good standing. Further regulation and licensing wouldn't prohibit those in good standing from obtaining even if they had mal-intent. This is why the argument for repeal of 2nd A is stronger than further regulation. However, the philosophical implications of a repeal are huge and would fundamentally alter all aspects of law and life in America.