Earlier quoted context omitted.
NK is aiming the weapon at US and its allies, unlike India or Pakistan who aim at each other. B.R. Myer's talk explains the motive behind NK's nuclear program pretty well. http://www.booktv.org/Watch/11315/The+Cleanest+Race+How+Nort...
Right, so it makes sense that the US would be worried... not why the UN should sanction them. I'm referring to the inconsistency. The implication of what you are saying is: "The UN only intervenes when it suits the US". To me that makes me think LESS of the UN sanctions, not more.
On consistency: I don't think UN, as a group of nations with conflicting goals, tries to behave in a consistent way, although people are free to blame it for its inconsistency.