One is from the Russian Civil War, the other from WWII. That was indeed the Stalin era, but remember, we and they were on the same side in that one.
I agree with the poster who said that these posters might be quirky and even what you might expect for a dorm-room or first post-college pad, but they really aren't the sort of thing you'd have around your place once you own a house and are raising kids.
It's similar to why they have multiple copies of the same books -- if it's not some photoshop era. These people aren't actually living in the house. I'm not saying it's an obvious front or beard situation, but their real lives -- if they have any -- are elsewhere.
Thanks - excellent comments.