I think the America parallels to this statement would be God, democracy, "our way of life" and such, references to which would not at all be unexpected in a letter such as this from the 60's.
Americans think "communism" is an icky political thing that Soviets were coerced to like, unlike "freedom and democracy (TM)", worthy abstract ideals that all Americans (nay, all Humans) should rightfully worship naturally and organically.
It's pretty amusing watching you trying to lay a trap and then beating up a strawman with your sarcasm. This letter was meant for the masses to read, and not to be kept in private between him and his family. Not the regional flair of political messaging it contains is telling, but the fact that it contains political messaging at all.
If my wive went on a risky mission and died about it, and all I get from her was a letter about "freedom", "democracy" and maybe "our great nation" and stuff like this, it would break my heart even more.
