Heinlein also wrote Stranger in a Strange Land which is about a bunch of hippies living together in a commune fighting against an oppressive state and wining.

I think calling Starship Troopers “fascist source material” is a bit reductive. Heinlein was exploring some ideas, not trying to make an argument for ideals. He had some issues, definitely, but just pointing to it and saying ‘fascist!’ ignores a TON of context.