One of the bigger questions asked in "Starship Troopers" was, "Should people who aren't willing to give to society be able to control that society's direction?" I say question, not statement, because I think that's what is intended.
The problem with this is that Starship Troopers isn't "just asking questions".
It's asking them and then answering them before you can even consider them, let alone open your mouth to answer.
It does this over and over. That's part of why it doesn't stop to let you think about the natural flaws of such a system, it immediately starts trying to paper over them.
This is further confirmed, note, by the fact that later on, Heinlein devoted part of an entire other book (on his work, I forget the title) to backfill and retcon on Starship Troopers, absolutely none of which was needed if your thesis about "just asking questions" was true, but which is exactly what you'd do if you believed the political ideology in said book had merit and needed to be protected.
You can make a much better case that Strange in a Strange Land was "just asking questions", especially as Heinlein later repeatedly rejected the ideology that the book suggests, whereas he's repeatedly defended the ideology that Starship Troopers suggests.
So let's not pretend this is all in some knowledge-less vacuum.
The themes are very heavy on Civic Duty and the topic of Civics in general.
No, not really. This is a weird thing to say in fact. The
start of the book is very heavy on that, and then its almost people forgotten in favour of weird xenophobic stuff which really LOOKS like it's trying to glorify corporal punishment and wars against Asian people (esp. as a lot of the accusations thrown at the nebulous enemy sound awwwwwfully like ones thrown at communist China at that time). Civics is rapidly forgotten in favour of macho naughty word generally.