"And you can say similar kinds of things about small towns and rural localities."

That is the point! It isn't the city or the small town that is "unfriendly" or "suspicious" - it is life in general. I think people who live in one environment develop an impression of another environment whether it is true or not.   New York is a very friendly town and once you know how the locals think it is easy.   If you or I were dropped off in a remote corner of the globe, I am sure the people who live their without contact to the rest of the world would look at us just as unfriendly and suspicious.

You can find good and bad wherever you look.   I guess it is a question of how you see the glass - half full or half empty. Some people will see it as half empty and the glass is dirty.