It's a clear sign that Johns does not understand Captain Marvel-which he never has, actually. But the real Captain Marvel hasn't appeared since COIE anyway-all Post-Crisis versions have gotten the character wrong, even Jerry Ordway's well meant and well done series. Captain Marvel is not Billy Batson in an adult body. They are two separate individuals who have a shared consciousness. They consider one another to be different people. That's where they got the character off track, which was actually in Roy Thomas Shazam: A New Beginning series, and then in the Giffen/DeMatteis Justice League.
Essentially, however, DC killed Captain Marvel with the lawsuit in the 50's and the character has never recovered and will never recover. All that is left of the Marvel Family is Black Adam as a Namor rip-off.