Oriana Fallaci relates a similar experience, IIRC, in one of her last articles. She was enraged, although being herself an atheist, at an Arab immigrant she saw pissing on the side of a cathedral. Reason? Because despite her atheism, she recognized that to be Italian meant that your culture was inexorably entwined with the Catholic Church, and to piss on a cathedral was to piss on Italy.
After leaving the KSA as a child and being basically raised Catholic afterwards, my own return to Islam as a young adult involved my desire to “reconnect” with my father’s culture. My mother quite clearly explained that it was not possible to understand the Arab half of me without understanding Islam. The two are even more intertwined than the Catholics and Italy.
Now, you’ve expressed the same cultural/religious link regarding Russia. Precisely. One cannot understand Dostoyevsky without understanding the influence of Russian Orthodoxy on the Russian culture. Can’t be done.
In the US, despite the fact that many of us are religious, culture is not intertwined with religion. Hence, Americans tend to misunderstand the cultures in the Middle East and in Russia. The average American, who does not consider these things deeply, simply does not understand a religiously-infused culture and how that changes what people see as “common sense” in such cultures.