While not a complete satire in tone, Starship Troopers was very much a "bildungsroman" showing a child growing up in that society and getting lectured about it and growing up (and growing more cynical as childhood naivety wanes). The book is extremely didactic and written "this is the way society should/must be", but that doesn't mean they were the actual didactic thoughts of the author (especially as the protagonist does start to question them late in the book, despite being a proponent of it all in youth). As much as anything the book seems to me a "gedankenexperiment" (thought experiment) meant to ask hard questions of an extreme take on a possibly good idea. The possibly good idea wasn't intended to build a militarized society, but the fact that it led to an awfully militarized one, seems to me to be an intentional contradiction in the narrative that Heinlein asks of the reader, in the way of a satire/farce (even if not actually satire/farce) to question the extremes of the thought experiment, to question the didactic lectures for their problems and failed assumptions.
Modern social media has beaten the idea of any nuance out of its consumers. I think it's very challenging for younger people today to understand satire and subtext, even the very concept of a thought experiment. When one's primary mode interaction with the world is short thoughts that are designed for maximum engagement and outrage, there's no room for subtlety. There has been a ratcheting effect of social discourse, and one who dares defy the orthodox positions, even to positions that were not controversial 10 years ago, draws the wrath of legions of anonymous mobs. Ultimately, people are rewarded for increasingly polarized discourse and disincentivized from moderation and especially from challenging thoughts. It's no wonder people are incapable of anything but taking something like Starship Troopers at face value.
I've been saying a bunch of similar things for a while now. I sometimes refer to it as being past a Poe's Law Singularity and good satire is hard/impossible/dead. Poe's Law examples (someone taking satire as serious surface level only takes) are too easy to find today, including in the very names of modern startups and corporations. RIP satire, you were a good friend once, and so it goes. It's possibly a good thing Vonnegut did not survive to see this world on the other side of the singularity. (Or it is possible it only happened because too many writers like Vonnegut passed away out of this timeline.)
In the words of Barry Humphries (RIP):
"If you have to explain satire to someone, you might as well give up".