So many personal opinions posted so far but no refutations that these dictators said they were atheists and/or evolutionists.
These dictators stated in their own words that they were atheists and/or evolutionists. See sossosoures listed.
As far as i am aware the only 2 "dictators" you list in the OP who said that they were atheist are Lenin and Mao Zedong.
So i suggest you provide your sources for your claim stated in their own words that they were atheists and/or evolutionists.
Certainly Stalin was known as the only christian in the kremlin. He rebuilt the russian church after the revolution, donated millions of rubles to the church and had not 1, not 2 but 3 church leaders officiate at his funeral. The actions if an atheist? I think not. However he was branded atheist 40+ years after meeting him (and after his death) by a fellow student. All accusations that he was atheist stem from this event.
Pol pot remained a buddhist all his life in that he never renounced his faith.
And hitler. Staunch catholic with vatican backing who governed over a willing protestant population.
"My feeling as a Christian points me to my Lord and Savior as a fighter." Adolf Hitler
"endow us with wisdom and the trust of our people, for we are fighting not for ourselves but for Germany." Adolf Hitler
"And now Staatspräsident Bolz says that Christianity and the Catholic faith are threatened by us. And to that charge I can answer: In the first place it is Christians and not international atheists who now stand at the head of Germany." Adolf Hitler
"The Government of the Reich, which regards Christianity as the unshakable foundation of the morals and moral code of the nation, attaches the greatest value to friendly relations with the Holy See, and is endeavouring to develop them." Adolf Hitler
And on, and on, and on.
Oh, and he was democratically elected.
Methinks you confuse nationalism and atheism