Virtually no one in D.C., Washington Post extremities included, cares whether or not D.C. is considered part of the Northeast I can assure you. Some people delineate the country that way (
http://en.wikipedia.org/wiki/Northeast_megalopolis,
http://en.wikipedia.org/wiki/Northeast_Corridor,
http://en.wikipedia.org/wiki/High-speed_rail_in_the_United_States), other people consider it the Mid-Atlantic, and in the end it doesn't have an appreciable affect on anyone's life here or in any other region.
The implication that the Washington Post (editorial board I assume) is trying to beguile people into believing that D.C. is in the Northeast, ostensibly for the aggrandizement of the city I guess, is especially rich though. D.C. needs to be included in that mix for what reason, so that people around the world can associate the city with Providence?* You're talking about the Capital of the most powerful country in the world, one of the most affluent regions of our country (perhaps the wealthiest depending on the metric used), one of the largest metro areas in the country, one of the two most important cities in the country, one of the most internationally connected cities in the country and one of the most culturally vibrant regions we have. Why would anyone living or working here feel compelled to dissemble about a regional affiliation?
Anyway, as it pertains to the next WC I'm very excited about the prospect of D.C. hosting the event, but I would certainly understand if some other city was awarded next year's game. There are a lot of great potential hosts out there, each as deserving a candidate as any other (the Avs, the Red Wings, the Sharks, the Wild etc.).
*No disrespect to Providence of course which is a very beautiful city imo.