Starship Troopers, like Fight Club and American Psycho, is a member of a select group of movies whose satirical intent sailed right over the heads of many moviegoers. It's a deliberately over-the-top take on the war movie as militaristic propaganda, a film that's taking the mickey with its cast of beautiful, sexy people with beautiful, sexy bodies, beautiful, sexy teeth and beautiful, sexy guns set in a future America where you're only allowed to vote if you've served in the military and agree that violence is the answer to pretty much everything. If you've played Helldivers 2, this is where that game got all its ideas (and its killer alien bugs) from.
A high school movie with a massive body count
Starship Troopers is based on the novel of the same name by Robert A Heinlein. That novel, published in the late 50s, is pretty fascist. But the movie takes the source material and subverts it. Director Paul Verhoeven absolutely hated the novel, which he said was "quite bad" and "very right-wing". So he amped up the fascism and made it so over-the-top that only someone very stupid would take it as a celebration of militarism.
Writing in Vice, Jason Bailey says that "in its early scenes, Troopers is basically a goofy high school movie, complete with love triangles, a big game, and a school dance (and sex) after. Once they've begun infantry training, the flexing of machismo so over the top, it can only be satire." The LA Times said that it is "a cheerfully lobotomized, always watchable experience that has the simple-mindedness of a live-action comic book, with no words spoken that wouldn’t be right at home in a funny paper dialogue balloon. Not just one comic book either, but an improbable and delirious combination of Weird Science, Betty and Veronica and Sgt. Rock and His Howling Commandos."
As Ian Nathan of Empire pointed out, this is a Paul Verhoeven movie with all that entails: it's "broad, brash and ultra-violent". As the Austin Chronicle put it, it has "a special effects budget that would shame the Pentagon, cataclysmic violence, high levels of ambient horniness, and total lack of pretense to any goal higher than pure, mindless fun."