Thats an interesting comparison... But NK is not firing weapons here in the US they are doing it in their own country so I don't think your analogy of firing within the city limits is comparable. I haven't seen reports that the missile tests they are doing as being an immediate threat to harming anybody.
Now your point about their threats is interesting. Im curious about what laws they are breaking by making threats? How their threats are different than the ones that Trump just made? And what is the punishment for making threats...
And to tie it back to the comparison in the OP... If a citizen makes a threat with their gun, "any intruder that tries to break into my house will be shot dead by my gun"... Should they be arrested? Should their gun be taken away?
You're right, N. Korea isn't firing weapons here in the US. If they did that, it would be considered an act of war. But my analogy still stands, because the missiles that they have test fired so far have been landing in international waters (the equivalent of shooting in the middle of the street), and if they carry out their threat to land some within 20 miles of Guam, those missiles will be flying over other countries (equivalent of shooting at someone through someone else's yard).
As far as the threatening? Yeah, again the analogy stands and N. Korea is doing the equivalent of standing on their back porch with a bullhorn, and threatening to shoot the person across the street. If you were to do that in the city limits, you would be charged with threatening, and if you had a gun in your hand and were shaking it (or test firing missiles), that would be considered brandishing.