Let's accept that Robert Heinlein's politics were all over the place, starting left-leaning and getting more conservative over time. (The irony of the Libertarian who popularized TANSTAAFL having depended on his government pension has been noted by many people.)
Perhaps you will get to this in the upcoming episodes, but reading Starship Troopers without mentioning the Nazi concept of Lebensraum or Carl Schmitt's friend/enemy distinction seems like it's missing the point of why this book was considered so controversial. You did lightly touch on the point that Heinlein, like modern zombie movies, creates a kind of war without PTSD, because the enemy doesn't matter.
Traditionally, the officer/enlisted distinction was supposed to keep the officers from developing attachments to the soldiers, so that they would not hesitate to send the men into battle. Since Heinlein was making the point that the humans cared about their soldiers, I wonder if that's why he had the officers all being former enlisted personnel.
FWIW: I knew Orson Scott Card back in the 1980s, back before he decided that if you weren't Mormon you weren't human. Ender's Game was, in part, a commentary on the abuse of child soldiers. It just seemed worth mentioning in this context.
Heinlein entered the US Naval Academy in 1925, graduated in 1929 and served on an aircraft carrier and a destroyer until 1934, when he got early retirement for medical reasons. That's almost 10 years in the military, counting his time at Annapolis. I'd assume that medical retirement was the source of the disability payments you mention.
When the USA entered WWII, he tried to re-enlist but was denied (probably for the same medical reasons), so worked as a civilian engineer/manager at the Naval Air Experiment Center in Philadelphia (with Asimov and deCamp).
His experience as a government civilian is coherent with his idea that everybody in the military should be a fighter. By working as a civilian, he freed up a naval officer to go work on a ship or fly a plane.
Heinlein was getting disability payments in the 1930s, which was exactly the sort of aid he would rail against later in life. Hence the irony. Also of note, he worked as an engineer in a shipyard during WW2, but he was not in the Navy.
Re racism, there's Farnham’s Freehold, which has Africans castrating white men, taking white women as concubines and eating white children - all while it's supposed to be an anti-racist book. And, while he did write some strong female characters, let's not get into the amount of misogyny in some of his books. As I said, he's all over the place.
I feel ST is at least partly a commentary on the reactionary politics of the 1950's (at least in America). This is the same time that Eisenhower is warning us against the military-industrial-congressional complex and right after Joe McCarthy and Roy Cohn went communist-hunting and ruined a bunch of people's lives. Heinlein can show us a future world without endorsing it. I'm pretty sure William Gibson doesn't want to live in The Sprawl.
Not quite sure what's ironic about a Naval officer relying on a pension he earned twice, once after WWI and again during WWII.