I'm not so sure they were trying to say it couldn't happen here, as it's well known these things have happened here. I feel like they were just giving his background, and the particular horrors he witnessed as a child to possibly explain some of his mental deterioration. In American cases, there have often been traumas as well-his particular extremes though, might be explained a little by how awful the conditions were in the war torn area he was born into.
I don't think they're saying it's the fault of the Russian society, but a lot went on there that might have damaged him.
Here, some serial killers emerged after the Great Depression, or after various childhood traumas..among other reasons. To deal with all that, in an unstable person, might create a shut down of his compassion, and contribute to his psychopathy.
My two cents.