Amish is essentially correct. This is more or less done intentionally so that people are free to create the superheroes they want, as well as to accommodate the fact that this is an unusual "comicbook" to begin with.
The "Sandtastic Avenger" isn't your run-of-the-mill DC/Marvel hero, and doesn't quite exist in comicbooks in actual Equestria. In this continuity/dimension though, he'd be something akin to DCAU Superman during his animated series run. (Not the JL version.)