Have we forgotten, or maybe never knew, that Socialism/Communism is declared atheism. Why would anyone expect ethical and moral behavior from them?
That being said Conservatism/Capitalism is not guaranteed morality either. Usually, they are closer to the Judeo/Christian ethic which has ingrained in it a level of accountability to God. This historically has provided a level of restraint as the fear of an ultimate judgment tends to produce that. (not intending to argue the finer points of grace via the gospel here
If one would take the time to read, "The Gulag Archipelago", Aleksandr Solzhenitsyn, or, "The Main Currents of Marxism" Leszek Kolakowski. There you would discover that Marxism in its deepest roots from the third-century Plotinest and on through to Engels, Marx. Lenin, you find a radical even violent atheism and an aggressive deification of man.
Is it any wonder from such an intense "spirit of Antichrist" evil has issued forth onto the shores of human history. 120,000,000 deaths have come forth from this evil. Marxism for out distances Nazism, Sixty-million dead. At times I wonder if this is the beast who had a deadly head wound and has come back to life. It seems incredulous that anyone unless demonized, would want any association with it? But alas the children were always their way, as it was then, so it is today. If not a child then one whose mind works like one. Thinking of a newly minted congress-women from NY.
Those great authors mentioned above have likened Socialism/Communism, to a disease and the medicine of a counter ideology, Capitalism/Conservatism will not cure it once caught. Only a healthy spiritual essence and demeanor in the culture will keep it from infecting and destroying the host. It is a social auto-immune disorder...AIDS OF THE SOUL!!