I wrote a paper in Superman a couple semesters ago, about DC Comics as an alleged Democratic National Party institution (Marc DiPaolo's claim, check out his book, it has Iron Man's face on the cover with an Obama campaign color scheme).
I see Superman as a man that teaches you that it's important for everyone to take an active role in reform, in a system of mutual dependence, and that Superman's enemies are all dysfunctional in the sense of being 'me-first', which is the big city, versus Smallville's collective conscientiousness of being a small town.
Lex Luthor needs to understand that he's just as indebted to his janitors as they are to him, and everyone in Metropolis is just as important, if you want to change the world, as the next kid on the street. But in a city, there's a 'trust fall' of unseen support, like with the financial system or the sewage crews or the bakers or the truckers. In a small town, you see everyone. And if you forget that, you're a Superman foe, for him to teach the value of individual valor and social justice to.