Why no nukes?

I don't understand all that is going on with N. Korea and why they are not allowed to have nuclear weapons. The whole point of having weapons like that, besides to end civilization on Earth, is to protect yourself, and why are we in the U.S. "allowed" to have nuclear weapons but WE say that other countries cannot? The reasoning I've heard is that we don't want a crazy person like whatever his name is having nukes, but don't we kind of have our own crazy person in this country currently in charge of our nukes? And wouldn't it make sense that N. Korea would fear that we might attack them.

I really feel like it's because of our current president that N. Korea is acting up the way they are. I think it's ok for them to want to protect themselves. I don't like the idea of being in their crosshairs as an American, but I suspect that if there were a war, we would find out pretty quickly that N. Korea is a lot stronger than we thought. Their people believe that Americans are evil. I think that all of their adults may very well be in the military or have served in the military, and could be called up at any time. I don't think we would be able to protect ourselves if they sent their aircraft all over here together. We should assume we are the stronger country. And we can't believe everything we read/hear about N. Korea. We know that they hear a lot of propaganda, and I'm sure we do, too. What we hear is what our government wants us to hear and what they feed us to believe. 

For now, I shall just remain under my bed waiting for doomsday.