If you and they can't do it, wouldn't it be easier to just admit that atheism is fatal to any effective assertion of morality, no matter how basic that is and that, therefore, atheists criticizing other people for their moral lapses don't stand on atheism to do that but, for the most part, they depend on ideas promoted as truth by the very religions they reject.
If you want to blame someone for making me come to these conclusions, I got them from listening to and reading what atheists said, not from any religious criticism of atheism. Atheism means anything goes as long as you can get away with it, in the end. That's not a new observation, as RMJ pointed out the other day, Nietzsche and Sartre are among those who admitted as much, not to mention other sciency atheists such as Francis Galton and Ernst Haeckel*, and, as I've pointed out, that masterful atheist judge of moral conduct, Steven Weinberg, for those who hold that philosophy is dead and has been replaced by science.
Christians who kill are violating the teachings of Jesus, they aren't violating your faith, atheism. I could ask that other question I did over at Religion Dispatches, where in atheism do atheists get the moral positions they use against religious folk?
* Haeckel's "Moral Materialism" included murdering a whole list of those he considered to have lives not worth continuing, the sick, the disabled (including the deaf) children, entire named races of people.... It also was an aristocratic system, opposed to democracy and socialism. His great work of science, the History of Creation, begins with a systematic attack on religious morality, rather odd for a book which was promoted as a great work of science by Charles Darwin. I doubt most sane people reading it in which everything must be reducible to a single characteristic essence, and what his monist system proposes as "morality" would be willing to consider it moral in any real sense of the word.
Update: "bitter blogging loser" Oddly I'm known as being remarkably cheerful by people who know me. Do I have to get out my theme song again? How about my other theme song.