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.