Why is It Called "Man of Steel" Not Called "Superman"?

An outstanding and Hollywood blockbuster is necessary for superior production team. Excellent story, a huge investment, the full control of power director, acting excellent actor and experienced post-production team are indispensable. And the Superman the Man of Steel appears to have almost all of the elements. And they spend a lot of money to make a lot of products about superman, for example, superman the man of steel t shirt, Kate Command Key, Clark Kent DC Command Key Cosplay Prop and so on.
Superman the Man of Steel is different with the previous five new Superman film, it has many highlights and innovations.

Superman the Man of Steel is facing the first question, why is it called "Man of Steel" not called "Superman"? For this, David Goyer Accepted Interviewed in Empire magazine, he said, we decided it was not a superman is deliberate, Chris Nolan and I decided to call it “Man of Steel”. That we hope that draw a line that the old Superman between the new Superman.
We knew we could use it when naming Superman symbols and symbolism, but we hope with the “Man of Steel" to represent us to create a new image, first because he is a man but he has not composed of flesh and blood people. So we use the “Man of Steel" to describe him, which is the reason we are so named.