Because the situation, demographics, pool of potential candidates, interest groups, organizations, and economics of NYC do not reflect the rest of the country. It doesn’t even reflect the whole of New York State. For example, the DNC forced Hilary onto the presidential ticket despite greater popular support for Bernie. Which is why we’re in this fucking mess to begin with, don’t forget. When one or more factors conspire in any given environment, results can be dra drastically different than if they were in a different environment.