There’s a few theories that I push over and over again when discussions on European social trends come up:

Communism was a “deep freezer” that conserved antediluvian (“based” in our lingvo) social attitudes in Eastern Europe, at least relative to countries under the American sphere of influence. These attitudes express themselves particularly strongly on LGBT, immigration, and nationalism. Russia is an organic part of this East European space (so a corollary is that any long-term democratic successor to Putin will be a right-wing populist in the mold of Orban or Netanyahu). The deep freezer broke down with the fall of Communism, with the subsequent thaw bringing “conserved” nationalist sentiments (or Islamist ones) to the surface. Consequent integration into the Euro-Atlantic information space – if to variable degrees – has promoted progressive views (“GloboHomo” in our lingvo) in Eastern Europe. There is now a race between new conversions to GloboHomo and the rate at which it is vindicated or discredited in its American and West European “early adopters.”

The latest PEW poll on social attitudes in Europe provides some of the strongest evidence for points #1-#3

Clear west-east gradient on openness to marrying into Muslim families.

Note that Russia is basically equivalent to Poland, so that puts the kibosh on any Eurasianist fantasies about merging with Central Asia.

Curiously, there is relatively less openness amongst Russians in the 18-34 y/0 bracket to marrying Jews than the average for Eastern Europe, even though they are also more philo-Semitic than everyone there except Czechs, Estonians, and Latvians.

Support for gay marriage displays an even starker east-west gradient.

The big exception is East Germany and Czechia, which are explained by local cultural quirks (e.g. Prague had a reputation for being a gay friendly city even during the late Soviet period); as well as Greece in the Western sphere (which, however, is still more progressive than its Balkan neighbors).

Incidentally, the Ukraine used to be more homophobic than Russia even just 5 years ago (at least as proxied by support for gay marriage). Now it’s visibly more LGBT friendly, four years after the Maidan. Belorussians have always been more liberal on this question.

Eastern Europe, especially the f.USSR, is the only region where Christianity has actually made concrete gains (more people currently Christian than raised as Christian).

Western Europe has undergone a deChristianization that the League of Militant Atheists could only dream of.

Most of Eastern Europe professes at least as much religiosity now as the most stereotypically religious nations of Western Europe, such as Italy and Ireland.

Rather unsurprising that the Scandinavians give the highest priority to “respecting institutions/laws” as a condition of sharing a national identity. Notable that only 62% of Ukrainians and 54% of Belorussians consider “ability to speak the national language” as important. That’s relative to 86% in Russia.

In contrast, all East Europeans do put a very high premium on ancestry, while Sweden Yes is conspicuously at the very bottom.

Commenter Polish Perspective has also commented on these polls.

Yes, we can see that the Hajnal Line explanations do play a substantial role – e.g., Portugal, Italy, and especially Greece are rather conservative relative to Western Europe – but these effects are swamped by the effects of the Iron Curtain, as well as local effects (e.g. Poland vs. Czechia on religiosity, whose roots may stretch back to more than half a millennium). To which JayMan would rejoinder, “But where does Communism come from?” (Answer: From where the Red Army met the US Army in 1945).