Nope, I don't think US has to do anything with China ICO ban and also nothing to do with North Korea as well. North Korea is so poor that they can't afford to have a computer in their home. And leave alone the crypto currency, North Koreans can't open an website which is not approved by their government. Chinese government's mentality is very similar to that of N. Korea. They believe that money is equal to power and that should be controlled in every possible way. Because if citizens have enough money, the power will be shifted from their government to their people. They want to curb that.