Personally I blame video games and movies. I know that's a totally overused argument but the idea of "the arena" is pretty ingrained in most people's thought processes whether they realize it or not.
Well depending on the city even streets and highways can be very crowded and as a result feel very small. Think about Time's Square, it's a huge open area with sight lines over 1,000 yards long, but try telling that to the guy walking down that crowded sidewalk or standing in the street during the New Year's ball drop, shit seems tiny. But, get everyone off the streets and you start to realize just how big and unassailable the place really is.
Edited to add an extra thought: This is something that's probably far more applicable to the majority of American cities than European cities though too since we tend to build in a grid rather than whatever the fuck the thought process behind Euro cities is. But even then the more modern and renovated parts of Euro cities are also very open.
And it isn't just that either, the dude is just downright whiny about everything.
Edited again since I just saw this too:
https://youtube.com/watch?v=rL5wePSjTL8
GT weighs in as well on the urban combat and survival subject.