How many were killed by Stalin, Mao and the Khmer Rouge?
The vast majority of those killed by those regimes were worked to death, killed for their political beliefs, because they happened to be in the way, or because of the paranoia of their leaders. Sure, some were killed for their religious beliefs but not many. Atheists were no more safe than the religious under those regimes. Everyone was a potential victim of those regimes up to and including the families of the dictators, or the dictators inner circle.
Still im very much against banning religion or any particular idea. Even when countries try to do that it fails or backfires on those in charge.
If atheists can paint all Christians with the same broad brush that they use for Televangelists....well then so can I....................?
Sure, if you want to you can. Not all atheists do that. If you criticizing them for something you do is just as hypocritical.