New Yorkers make a show of gibing tourists, I think partly because so many of the people who live here are transplants themselves; not so removed from those tourists they're bashing. New Yorkers still love crowning themselves "real New Yorkers," and evidently one of the keys to differentiating yourself as a real New Yorker is to ridicule the less real as they stroll these mean streets.
Ironically, New Yorkers spend a lot of time bragging about their city, so you'd think they'd interpret the unending desire of tourists to experience New York as a validation of their boasts. That Chinese vacationer who stepped on your shoe six times in the three minutes he was on the subway? He and the millions of others who visit each year are telling you you're right to be living here! No one in Baltimore has to worry about dodging tourists.
Another irony: Manhattanites frequently crow about how many countries they've visited. On the dating site OkCupid, under the category "Six Things I Could Never Do Without" (surprisingly, I am never on these lists), every New York woman lists 'passport" as one her six things. You'd think people who are so often tourists themselves would have more sympathy for the travelers who are checking NYC off their list.
I'm a real New Yorker, and I'm about to let you in on a little secret: It isn't the foreign tourists that chafe New Yorkers; it is the American tourists from the South and Midwest. They are the unwashed menace New Yorkers view as reprobatic, cultural Luddites. Doesn't matter how green their money is; their states are red, and that makes them the enemy. The current New York mentality is an inversion of the film Death Wish, with people fleeing TO New York to escape the threat of suburbs and small towns. The difference is that while Death Wish is largely fantasy, the danger present in that New York was fact. The danger posed to New Yorkers by Southerners and Midwesterners is entirely fantasy.