Presumably you are referring to Stalin, Pol Pot and more. Almost all free thinking secularists, have condemned them right from the beginning. They were pursuing a communist agenda and were just as ruthless against secularists as against religious people. Their dogma was the communist manifesto not secular morality as it had evolved to that point.
Atheism, as you should know by now, makes no statement other than they do not accept any proof that has been provided to date that there is a God (although willing to change their view should evidence to the contrary be forthcoming). Some atheists go farther and say there is no God. However, that's it, nothing more, even if you erroneously want to ascribe other beliefs to it. What views atheists have on other topics, including morality, is of no consequence, as it is individual to each atheist and inconsequential to the position that they do not accept that the existence of a God has been proven.
I have no problem condemning the atrocities of communist dictators, whether they be atheists or not. Their actions were and are repugnant and are absolutely immoral according to my moral values.
It astounds me that you should still refer to atheism as a religion as if it had tenets beyond that of a statement on God's existence. It seems that having now established that you are quite willing to absolve your religions of morally repugnant acts, you think by bring up the old atheism bogey you can turn the tables. Nope, that doesn't work. No problem from my end condemning morally repugnant acts, no matter who does them. If Stalin did not accept the existence of God for the same reasons as I do not accept God's existence, that doesn't in any way lead me to try and defend his actions.
Conflating secular morality with atheism shows me that you have lost the argument. If you think Stalin was trying to follow the secular morality that had been developed and espoused by say the Founding Fathers of the US (many who were religious but opted for a secular system of government based on secular principles) or by great thinkers like Bertrand Russell, then that is quite preposterous.
Religion is like the various channels on a TV. Atheism is simply the off button. It is not another channel.
No! You have almost completely misunderstood my post, and are arguing points that were never raised.
My argument against the existence of "secular morality" is not based upon my theistic views, it is derived from the observation, that by its very definition alone, morality simply cannot exist in an accidental or unintended universe!
My reason for mentioning and condemning the prevalent practice of the "HolierThanThouism" religion, was my effort to alert yourself, and those of your ilk, to the reason I believe that the anti theist's enmity for Christianity, Islam, and theism generally, is misdirected.
I have witnessed the all too prevalent, practice, of "HolierThanThouism", by numerous people, including some Christians, Muslims, atheists, agnostics, "agnostic atheists",anti theists, socialists, capitalists, communists, scientists, humanists, naturalists and "none of the above"ians, just to mention a few!
And its practice, is almost certainly the common denominator, in almost every, human dictated, atrocity, including those that "HolierThanThouists", gleefully cite when condemning somebody else's religion!
I agree that a position of doubt, or even conviction, in the nonexistence of deities, does not make atheism a religion. However, many atheists, by their own choices and behaviours, have made atheism their religion! Do you understand the distinction I am making here, (it strikes to the heart of the true definition of religion)?
To use the television off button is not a channel analogy:
Having the button in the "Off" position does not make one an "OffButtonist", however, obsessing about the fact that the button is being left in the "Off" position, does make one a member of the "OffButtonist" religion!