Right now the politics is shit. And hence we aren't able to relate to this. And it would be insane for us to write a letter to loved ones with political statements. But at that time, when it was a national movement, maybe it wasn't that odd.
If he were a doubter, it would still make sense to include that to potentially make it easier for his family to obtain or preserve a decent position in the Soviet society. These sorts of heroes were supposed to be idols and demigods of the country. This wasn't a society that would respect you having a private apolitical part of life, especially for a man of such a position.
I almost wrote how people are clueless about living under totalitarianism, where there can really be no such thing as truth or honesty. Except maybe heavily drunk in a small company in a dacha, if you're feeling adventurous. But really I think people would often pay lip service to any social orthodoxy in such a situation (contrary to what you might think), because of the benefits of psychical comfort and fitting in.
Now let's apply this to the modern days, where declaring yourself as a conservative can kill your career and activists feel justified in screaming to your face on the street if you refuse to regurgitate their rally cries.
Much of the bill of rights is about what the state can't do to you in a way that doesn't impact how private citizens interact. Not saying it's perfect, but I'm far less concerned about an internet mob coming after me than the US government
> Raise them as people who will deserve to live a new communist society.
> I wish to dedicate this flight to the people of the new communist society...
Would it seem political if someone wrote:
> Raise them as people who will deserve to live a new capitalist society.
> I wish to dedicate this flight to the people of the new capitalist society...
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!
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.