Just to play devil's advocate: Could 'On' refer to which SIDE the man was located at? I mean, I agree that taken as the name of a neighborhood, "IN" would be more appropriate, but in the strictest sense of the term, I would say that I'm ON this SIDE as opposed to that one, or that she's ON my side of the block.
Since SIDE implies a number of other theoretical sides that aren't this particular one at hand... If nothing else this is evidence that the editor/journalist of the article in question may not necessarily be a native of New York.