You've been seriously mis-informed:
Greek warrior Spartan civilization. Weakling infants were left in the mountains to die.
The Republic, Book 5, Section 1. Plato recommended state-supervised selective breeding of children.
History of Australia. Before Darwin, England exiled criminals to purify the race.
As for socialism, it has an ancient history. It existed and was practiced long before Marx. In recent times the Mayflower passengers practiced "bible communism" when they arrived on these shores. There were many communal societies before Marx, too many to recount here. And as for Darwin and socialism, Darwin's Influence on Ruthless Laissez Faire Capitalism. ICR (the granddaddy of all creationist websites) links Darwin to good ol' capitalism.
I'm not misinformed. You have added to the information, with historic brothers of the modern day eugenicists.
However, there is a definite corelation between the various national Eugenics Societies and socialism in the mid- to late 20th Century. Julian Huxley's writings and speeches on evolution and Christianity should be evidence enough.