The atheist religion is political correctness.
The other thing is their claim that science should decide everything; not involving ethics or morals. Hitler and the Soviets used the “science” of psychiatry to murder and torture millions of their victims.
While atheists can be relatively moral people, operating out of objectively baseless moral reasoning, they have no standard one can hold them to, and can justify removing children of Christian creationists parents as easily as Mao could justify the murderous means to achieving his end.
So can those in religion, except for NT Christianity.
While I am sympathetic to your POV, I have never seen the number 200 million anywhere else in regard to soviet atrocities. I think that it is highly important to stick to the truth when we make our arguments. Do you have any data to back up that number? Sources would be helpful.
So, going back to the days of Constantine, you would bet that atheists have killed more people in the twentieth century than all the Christian Popes, kings, nobles, explorers and presidents have killed since 300 AD? Very bold!