The fact is Atheism itself isn't a principle, cause, philosophy, or belief system which people fight, die, or kill for. Being killed by an atheist is no more being killed in the name of atheism than being killed by a tall person is being killed in the name of tallness.
People were killed in communist nations for a lot of different reasons. Some were communists who disagreed with those in power and were killed because of that. Some were anti-communists and opposed the government and were killed for that. Some were simply in the way or inconvenient and were killed for that. These are political disagreements that people were being killed over, not murder in the name of atheism. Communists typically regarded religious organizations as a hinderance towards the creation of a worker's paradise. Even if some people were killed simply because they followed a religion, that doesn't mean they were killed in the name of atheism.
To further illustrate this point, take the Inquisition, how many people were killed during the Inquisition in the name of theism? None. Those doing the killing acted not because of theism, but rather because of xian doctrines.
Communism is not, inherently atheistic. It is possible to hold communist or socialist economic views while being a theist and it isn't at all uncommon to be an atheist while staunchly defending capitalism. Their existence alone demonstrates, without question, that atheism and communism are not the same thing.
Perhaps it's Christianity which is inherently communistic? After all, there is nothing in the gospels which even so much as suggests a divine preference for capitalism. On the contrary, quite a bit of what Jesus said directly supports many of the emotional foundations of socialism and even communism. He specifically said that people should give all they could to the poor and that "it is easier for a camel to go through the eye of a needle than for someone who is rich to enter the kingdom of God."
Sure, I'll argue that with you, you start.Do you think that these mass killings could have occurred in a Democracy? Do you honestly want to argue that the Nazi’s were the result of democratic processes?
What mass killings are you referring to? Could you provide examples of the mass killings, as in, -on X date, in X country/city etc. X number of people were killed by communist forces.