I write this condensed version of the connection of Darwin to Marxism, and trust that it may reveal to many why Darwin should not be taught in schools (even as a “theory”). And that Darwin’s theory of evolution supports a main pillar of socialism, which has failed each time it was implemented in part because of this godless premise.
First, know that Charles Darwin and Karl Marx/Frederick Engels were contemporaries, whose works were published in the same time period.
From Marx: “Nothing ever gives me greater pleasure,” said Marx in the late 1860s, “than to have my name linked onto Darwin’s. His wonderful work makes my own absolutely impregnable. Darwin may not know it, but he belongs to the Social Revolution.”
Engels wrote to Marx in 1859, just after he had read the first edition of Darwin’s book (“On the Origin of Species”): “Darwin, by the way, whom I’m reading just now, is absolutely splendid. There was one aspect of teleology that had yet to be demolished, and that has now been done. Never before has so grandiose an attempt been made to demonstrate historical evolution in Nature, and certainly never to such good effect.”
It was critical to Marx and Engels to repudiate all forms of religion. “The anti-religious sentiments of Marx found further expression in his (doctoral) thesis when he chose for its motto the cry of Prometheus: ‘In one word-I hate all the gods!’ … While Marx was at the University of Berlin he fell in with a left-wing school of Hegelians who were followers of the German philosopher, Georg Wilhelm Hegel. At that moment their whole energy was consumed by a desire to liquidate Christianity.”
What Darwin’s theory of evolution had done was, as Engel’s put it, “demolish” the early theory of a “divine designer of all life”.  It gave “legs” to his socialist/communist beliefs.
However! In recent decades, the understanding of biology (especially DNA and related subjects), along with the mathematical improbability/impossibility that a random collection of molecules could create life, have led to an undeniable conclusion that Darwin’s theory of evolution (and the similarly posited Marxist dialectical materialism) was wrong. There is a video from the series “Uncommon Knowledge” (Hoover Institution, available on YouTube) named “Challenge to Darwin.” The discussion in this video revolves around an essay written by David Galernter wherein, after reading Stephen Meyer’s book “Darwin’s Doubt,” he no longer believes Darwin’s theory. All three members of the panel (Galernter, Meyers, and David Berlinski) agree that if, in 1859, Darwin had the knowledge we have today, he would not have proposed his theory of evolution.
Basically, the theory of evolution, and dialectical materialism; a pillar of Marxism/socialism, have been debunked.
Further to that, Stephen Meyer’s (Discovery Institute) video “God and the Origin of the Universe” makes a compelling case for the Intelligent Designer—God. Towards the end of his talk, he recites a quote from astronomer Robert Jastrow. “For the scientist who has lived by his faith in the power of reason, the story ends like a bad dream. He has scaled the mountains of ignorance; he is about to conquer the highest peak; as he pulls himself over the final rock, he is greeted by a band of theologians who have been sitting there for centuries.”
Socialism has been making inroads into our society for decades, through the elite class, power-hungry politicians who want to rule over us, to socialist judges who legislate from the bench and who, in 1963, wrongfully removed religion from our schools—religion, upon which our founding principles were laid.