And yet these socialist societies were much more successful than many Christian nations. Matter of fact, Soviet Russia was far more prosperous than the Tsarist Russia, proving you wrong. in 1917 Russia was a century behind the most developed countries of the world and the majority of its population was illiterate - just like the Orthodox Christian patriarchs liked it. The godless communists went through that missing century in 30 years and the literacy climbed to over 99%. Nowadays Russia becomes more and more Christian again and fails more and more economically. Cuba is in every way better than Haiti.
Here is more food for thoughts: the poorest country in the world is Christian. Out of 10 poorest countries in the world, 6 are predominantly Christian and two more are 50% Christian. A lot of that poverty is directly caused by religion, because, like I already mentioned, illiterate population makes devout Christians - they listen to everything the church says, no matter how much the church distorts the reality.
Seriously, disavowing the church was one of the few things communists did right. Religion is a serious hindrance for progress.