As a pastiche of fascism, you have a point. Juxtaposing the blatant nazi imagery with everybody in a position of authority being unbelievably stupid and self-destructive, classic stuff. But none of that has anything at all to do with the books.
Like, the triple-amputee recruiter? That was actually in the text, in the first few pages that the people making the movie bothered to read... but a little bit later you see that same guy who was doing the recruiting walking around just fine with all his arms and legs attached.
So Juan Rico (yeah, the protagonist of the books was Filipino, because Heinlein was making a point about how true strength as a society requires diversity, before the movie decided to replace him with a blond-haired blue-eyed Johnny) goes up to the guy and asks what's up. Turns out that the recruiter, like anybody else injured in the service of their fellow man in the Federation, was provided with top-quality cybernetic replacements for free.
He only takes them off when he's recruiting, because having a visibly crippling injury or deformity is a prerequisite for being allowed to tell kids about their options for a military career. The whole point of his job is to force idealistic youngsters to confront the true cost of military service and try to convince them to do literally anything else with their lives (like one of the many, many forms of service that give you all the same citizenship benefits but without any physical danger).
The people making the movie either never got that far, or decided to ignore it. Which is why the crippled recruiter is presented as nothing but a joke about how incompetent the military is and how desperate they are to get every single recruit they can to replace the ridiculous casualty rates of their incredibly dumb tactics.
And this kind of thing repeats over and over across the movie. In both stories, the Federation began when military veterans staged a coup against the civilian governments. In the book, they did this because they refused to put up with a bunch of politicians throwing away millions of lives in pointless forever-wars for their own profit while never personally leaving the safety of their luxury estates; the core ideal was that nobody should be allowed to order another person to kill or to die without first knowing what it's like to put themself at risk for the protection of others, which then expanded out into nobody being allowed to vote on matters which control the lives of billions without first spending their own time in the service of others (any kind of service, only 5% of modern "veterans" were actually ever in the military and the majority of those were in administrative or support roles). In the movie, the military took over because they just wanted power and restricted citizens to military only in order to maintain a stranglehold on society.
In the book, the Bugs are one of several dozen alien races the Federation has encountered, and the only one that they aren't peacefully trading with, because the Bugs are genocidal colonialists who have been exterminating their way across the galaxy and refuse to negotiate. In the movie, the Bugs are the first alien life that humanity has ever encountered and the military immediately launches an unprovoked attack on them.
In the book, Mobile Infantry refers to a small group of elite, highly trained, power-armored volunteers so powerful that deploying them within a kilometer of each other is considered to have an unacceptably high risk of friendly fire, and so rare that every time they kill a thousand enemy soldiers at the cost of a single MI life, they consider it to have been the enemy's victory. One of the big recurring themes is that an army made up of volunteers, with proper gear and intense training, under the command of officers who care about them, will always outperform an army of cheap conscripts led by people who spend lives like ammunition, regardless of how extreme an advantage the latter might have in numbers. In the movie, the Mobile Infantry is a huge legion of barely trained kids with crap for equipment who are sent to die for no purpose.
