This is hinting at a deep, and vital, storytelling aspect of the Marvel universe. The Marvel superheroes depict men as gods, rather than gods as men. Tony Stark is Iron Man. Superheroes such as Batman or Superman identify themselves as their heroic personas, and have made a complete commitment to heroism. Bruce Wayne is Batman. The man is actually the mask that hides his true self.
Many Marvel characters have heroism thrust upon them, and our enjoyment of the story often comes from how these normal people respond to suddenly being much greater than a normal person. We as an audience enjoy Marvel stories because we love the people behind the heroes, and by calling them by their real names we hint at this overarching storytelling element.
Of course, there are always exceptions: Captain America feels like a DC hero thrust into the Marvel universe and made to deal with a morally gray world.