Go thou and re-read your history. Marx's main works predated Darwin and Marx's most consistent practitioner had "Darwinists" dismissed from teaching and some executed. Fascism is a derivative, sort of Spaghetti Marxism.
And yet even to this day the "theories" of Marx's great epigones Engles and Oparin form the basis of NASA's research into "origins of life":
NASA is totally committed to the Oparin dialectical materialist speculation on the origin of life. Most of the origin of life projects supported by NASA ... are "proteins first" and are due to go the way of perpetual machines. They may produce interesting chemistry but they have nothing to do with the origin of life....One must suppose that the epigones were intimately familiar with the thought of their master, and were faithful proselytizers of it, the comparative publication timing of Marx's and Darwin's principal works notwithstanding. I imagine that Darwin would not have approved of his theory being reinterpreted into the categories of dialectical materialism. But seemingly this has been done anyway, as NASA's commitment to Oparin (that nasty Soviet beast!) clearly shows.It is a characteristic of the true believer in religion, philosophy, and ideology that he must have a set of beliefs, come what may.... Belief in a primaeval soup on the ground that no other paradigm is available is an example of the logical fallacy of the false alternative. In science, it is a virtue to acknowledge ignorance. There is no reason that this should be different in the research on the origin of life. The best advice that one could have given to an alchemist would have been to go study nuclear physics and astrophysics, although that would not have been helpful at the time. We do not see the origin of life clearly, but through a glass darkly.... [Hubert Yockey, Information Theory, Evolution, and the Origin of Life, 2005, p. 182f.]
Hitler's racialist policies were undoubtedly justified on "survival of the fittest" grounds, that entailed that people considered to be "less fit" could be expunged. Peter Singer continues to make that argument today, from the hallowed halls of Princeton. You don't think he got that idea from the Gospel of Saint John, do you?
FWIW Doc. Thanks so much for writing!