Bear in mind that the project wasn't originally connected with Heinlein at all, but was originally titled Bug Hunt. Only later did Verhoeven and company come across Starship Troopers, realize that they could actually get the film rights, and rework their existing script to (kind of) match the novel.
Oh now that makes sense. I left the movie theater HATING that movie so much. I believe I said out loud, "Did they even read the book or just the first chapter!" My friends reply for everyone to hear, "NERD HATE."
Films are not books. Some very good films (such as Dr. Strangelove) may be inspired by a book or riff off it but end up in a very different place with a very different tone. It's not a filmmaker's job to do a faithful adaptation--although those can work too.
