I have spoken to a western Communist who blamed inefficiencies in the Soviet Union on Russian culture, calling it "Byzantine" (an incorrect assumption in my view, but I have no interest in defending Communism or hating Russia like he did). I was simply wondering if there were other tales of encountering this sentiment.

May be I'm amaze you, but he was kind of right. :) From the Western point of view, any implementaion of Russian civilization will be ineffective. That Byzantine thing without quotes also have noticeable influence on that. Western and Russian values are different, so this inefficience. Soviet Union at the times of Cold war was not about GDP or quality of life or opportunities or profits or whatever value he had in mind. It was about providing some meaning and sufficient level of life for every single citizen. And USSR was very efficient on that. Thanks to that USSR approach around 80% of Russians are owners of their own housing f.e. Or have more or less decent education.

Another thing related to this "unefficiency". Western companies had extremely hard times when after USSR fall they tried to open local branches of their business in Russia. And they failed to resolve them. Thing is in the attitude to the labour. Average Westerner work because it is in his list of virtues. If you will work good, you will become wealthy and all that stuff. (at least things was that way in the not so distant past.) Protestant ethics and other things. And now I tell you something that will blow your mind or give some useful clue. Russians never work. You could force Russian to do some job, but this will end pathetically. No money or virtues could force Russian to do a job at same level as Westerner. Russian will always try to find some higher purport in doing something. If there is no purport found, then it will be unefficient immitation of doing job, But if we see some decent sense in something, it still will not be a labour, it will turn into a feat, mission of life or hobby of highest level, but in no way it would be a labour in the western sense. This is the reason why we have spaceships and nuclear icebrakers fleet along with other technological miracles, but can't produce decent cars. There is no any higher purport for us in copying millions of identical things. :)

The way Christianity and other cultural elements were repressed by the governments established after both revolutions, and the blood of innocent French and Russians was too high a price for the ideals implemented, in my opinion.

For a long time I'm trying to explain to my western fellows what Russia is, as historical and societal entity. It is not some leadership that change Russia. It is Russia that eventually always change its leadership. Just like in that "paradoxical" jokes started with "In Soviet Russia NNN do MMM". Russia had and still have a lot of shit, but it always eventually devour shit that doesn't benefit this strange entity. Bolshevik oppression of Christianity was eventually stopped by Bolshevik Stalin when he got enough power to oppose Jewish Bolsheviks. And all those who do that shit was severily punished one way or another. Christianity then existed in USSR kind of unofficially but to the level that most part of Russians born in USSR was baptized into Orthodox Christianity. Including me. Atheist USSR created on the ruins of Russian Empire by insane Jewish Bolsheviks eventually celebrated Christian holidays and keep Orthodox traditions through the times. Even state owned bread factories had government standard for Orthodox Easter cakes that always baked on the eve of Orthodox Easter. Officially they named like "Spring cake", but it was traditional Christian dish.

Meanwhile other civilizations are also different from Western one. But for unknown reason, Western elites sure that everything around should be measured with Western gauges, and if someone doing things in their own way, it is bad and evil inherently and should be defeated at any cost. Such delusion will eventually destroy Western elites, and I hope they will not have time do fuck the world up.