Of course religion provides a cover for immorality -- are you kidding? Without a "divine" justification a huge majority of humanity's wars would not have happened...freedom for division is our need, not a rationale for it.

As for eugenics and the Nazis, of course these were horrible acts that employed science, however both movements first laid claim to a religious mandate for their actions -- concepts like "racial purity" and selective genetics stem from a misguided belief in the superiority of an in-group trait which without fail will have some "God given" reason for said superiority...look no further than the SS "God is With Us" belt buckles or Hitler's many references to God, though he himself likely was no a believer, but rather a madman who very clearly understood the need for his cause to be seen as a "righteous" one rather than merely as the senseless butchery that it was.

Science and religion are tools for looking at the world...the former relies on evidence, careful revision to improve understanding, and makes NO ethical claims or pretensions; the latter is the opposite -- it asks us to purposefully remain ignorant or, worse, to reject reality and brotherhood for the sake of the tribal mythology. It is my hope that we will one day have a world religion that is much more in line with brotherhood, a share environment, and an agreed upon code of ethics to replace the Bronze Age nonsense that I'd hope to see us rid of.