User blog comment:GodzillaDestoroyah/GMK represents WW2?/@comment-1488423-20140510014308

You could say that GMK is metaphorical for WWII, except you have the roles a little reversed. The movie is about the atrocities and war crimes committed by the axis (namely Japan) during WWII. They even give this as Godzilla's origin story in the movie, that he was re-animated by the vengeful spirits of those that Japan had committed war crimes against during the Pacific conflict, and they were getting vengeance in the form of Godzilla. So it's more like Godzilla is the Axis, while the Guardian monsters could be the Allies. Except this would be a total role-reversal considering that Godzilla has been one half metaphor for the unstoppable American military, one half metaphor for the devastation of atomic weaponry since his first appearance.

TL;DR You COULD say GMK is a metaphor for WWII, but it's very thin connections and you have to do a lot of stretching and grasping. Better to just take it at face value for what the movie itself says it is.