The reason big city cats act like they are superior is because they come from an environment where competition is fierce. You have people from all over the world attracted to big cities where salaries are higher and general standards in everything are higher. The competition to get to the top is that much harder so if you do make it in a big city, you're doing well.
This is not an excuse for acting like an a**hole. I grew up in London and I used to look down on anyone who wasn't from London (apart from maybe people from New York). Now I live in Cape Town so I have felt what it is like to be looked-down on by people from Joburg. I'm a reformed big city a**hole