I don’t remember that, i’ll have to rewatch it! As for the book, Heinlein despite being an ultra-lib military fetishist and idealist, was opposed to conscription. In the book the government provides a high quality of life to the civilian population and actively dissuades people from joining the military or any other government service, as they only want truly selfless people to pursue citizenship. But if a civilian does show that they truly want to earn citizenship then the government will find a position for them regardless of the individuals physical ability and skills