Superman stories as morality play?

[Soubhagya]

I found a short interview with Elliot S! Maggin. Its nice to hear his opinions on his experience as a fan and a writer of Superman. Some of his opinions can be seen as controversial. Most modern fans think Clark Kent to be the real guy. What really intrigued me is his idea that Superman stories aren't typical action adventure stories. But plays on morality and ethics. Can someone explain this to me a bit more? I haven't read most of his work. Its kind of refreshing to see someone point that many writers approach writing Superman by depowering him.

Here's the short interview.