Does the atheist promote his godless faith to undermine sexual defenses?

Prominent atheists frankly describe their antipathy toward sexual morality to justify their rejection of Christianity:

"The worst feature of the Christian religion is its attitude toward sex" (Bertrand Russell, Why I Am Not a Christian, p. 26).
"The divorce between the sexual life and fear can now at least be attempted on the sole condition that we banish all religions from the discourse" (Christopher Hitchens, God Is Not Great, p. 283).

Atheism in the service of sexual promiscuity was also advanced by Nietzsche and de Sade. Isn't the prime motive of the atheist to take advantage of vulnerable young women and/or men by telling them that sexual promiscuity has no moral consequences?