Metaphorically speaking, the cops around town that "keep people in line" are just like people in life who "make the rules." They're there to enforce social norms; thus people who say "this is just how it is" when faced with a new situation. Point being, not enough people are willing to ask "why?"

Not arguing the technicalities of crossing the street or why laws are made, just noting parallels between a decision that people make unconsciously every single day and its relation to life and the "big picture."