It’s a send up and mockery of American culture around their military. It is parody, quite mean parody (as is typical of Verhoeven), and it wasn’t well received at the time (in the US).
As an Australian, I laughed heartily, and considered it just deserts for that Simpsons episode. ;-)
The movie is a commentary on the seductiveness of Fascism.
Verhoeven is something of an expert on this, since he grew up in The Hague during Nazi occupation.
There's an interview out there where he says when he making the film he was wondering if his movie was in-your-face enough about Nazis, to really make sure his movie wasn't too subtle or that people would miss the point he had the former Doogie Howser actor wear a SS officer's trenchcoat.
As an Australian, I laughed heartily, and considered it just deserts for that Simpsons episode. ;-)