I'm far more understanding of tourists that block the sidewalk traffic flow than the mindless long-term residents of the city that do the same. Tourists are unfamiliar with many of the areas they are in and are looking around at various attractions and things, while helping boost the city's economy by spending their money here.
I agree on the need to be understanding as a city resident or worker. At various points in my life I worked in Union Station in Washington DC and Times Square in New York City. You just knew that at certain times of the year you were going to be in a mob, many of whom were from out of town and didn’t understand “city” walking rules. City folk like the idea of living in a town with a million tourist attractions but they get annoyed when tourists actually come to see them. When a tourist does something like stand at the top of an escalator and I say “excuse me”, they usually react like they didn’t understand they were doing something wrong and move.