My reading of the Heinlein SST was pretty much ‘militaristic service for citizenship’ with an option of ‘service for citizenship’ but that not being as good as risking your life.
Of course, that does mean there has to be something for the military to risk its life for … constantly. Now, maybe Heinlein did mean for his whole book to read like that: the constant war, military service, only those who serve being worthy of participating in society, all that to be read as bad … but it’s just not in the book. Many who read it also don’t find a critisism. And Heinlein himself? Well, he always said his book spoke for itself and hid nothing.
The problem is that his only requirement for having a say in society was service: no service, no say. Doesn’t matter if you’re an idiot, saint, arsehole, brilliant strategic/economic thinker: no service, no say.
Which is antithetical to the thought that everyone who lives in a society should have a say in it’s running. Because it affects you and you affect it, you should have a say in it.
Verhoeven, funnily enough, never even read the book (just two chapters, almost, before he decided he hated it). I was shocked at that. The unrelated script called Bug Hunt at Outpost Nine written by Edward Neumeier just had so many similarities to SST that they bought the name. But the film just absolutely skewers the book, almost as if it had been written as a direct rebuttal.