I'm not comfortable with any country in the world having nuclear weapons. That being said, I don't see how any government currently has the moral standing to stop any other government from doing so.
No, I don't suppose anyone sophisticated thinks that. It's not really about morals so much as political pressure, I think. The idea is to limit nukes as much as possible for as long as possible, because they wider they spread, the more likely they'll be used.
I'm absolutely concerned about the fate of those troops. I urge that they be brought home immediately where they belong. That being said, South Korea itself is far superior to North Korea, technologically speaking, and, while North Korea may have superior numbers, with the U.S. backing them there's nothing North Korea can do, and North Korea knows this.
So you think the tripwire troops should come home......they are written into the Armistice treaty, of course.
You are thinking, I gather, that SK can defend itself effectively against the Million-Man Army and that our support would not be either with ground troops or by an all-out war declared by the USA. What sort of support from the U.S. were you envisioning in the event of that huge NK army crossing the DMZ and heading south? IIRC, it's only 30 miles to Seoul. They could get there very quickly.
Another thing North Korea knows is that if they do something really stupid China will not support them, which means they would stand less than no chance. So they can be as bellicose as they want, but they're not going to make any serious moves without China's blessing, and China has no interest in a real conflict with the United States right now. They're more worried about Japan and the Senkaku Islands than they are North Korea as far as I can tell.
We can't control Cuba; I don't think China can control North Korea. China hasn't been able to control Taiwan all these years either. I'm not sure rogue dictators have masters. That's not what happened last time --- last time NK just charged across the border, as we are afraid they will do now. Eventually, when our forces went north, the million Chinese poured south over their border, and forced the Armistice, but if I understand correctly, the Korean War was not China's idea, it was the first Kim's idea. A new one could be an independent action of the third Kim, I think.