N.Korea and nukes

So we have a bunch of countries possessing the nuclear weapons. Now why are these countries denouncing North Koreas actions. It is kind of understandable if say Chile, Fiji, Nepal, Monaco, Grenada or the Vatican City take issue that the world is getting dangerous.

Are the countries that already have these weapons taking any effort to reduce the numbers of these weapons? In the 90’s mainstream media used to carry news about countries trying to reduce their stockpile. I have’nt read any thing for sometime on this reduction. Anybody know what is happening?

edited: changed the word ‘people’ to ‘countries’