Yes, modern OTL liberalism is sort of societism-lite. But unlike the USA, the USSR explicitly wanted to be a world state, and while it did not openly deny cultures and languages the right to exist, the attempts to make them conform with Moscow's vision were hugely disruptive. In a way the USSR might seem more dangerous than the Combine, because the latter was honest about its intention to destroy all existing cultures, while the former was sneaky enough to officially promote them in very cases even as it destroyed their substance. Maybe they will think that this is the reason why OTL is so terrible. Without an open challenge to the existence of nations, diversitarian-like ideas are less appealing.
Also, if the crosstime expedition from the LTTW timeline studies OTL history, they will find that Stalin's concept of exploiting divisions between capitalist states was very similar to their history's Doctrine of the Last Throw.