I'm heading out the door so this has to be my last till Monday.
But of course I think you're wrong.
You as an atheist are dictating to me what Christianity is. Makes no sense.
Many atheists are students of Christianity and Christian history, many of these people understand Christianity better than the believers. I am not claiming to be a leading scholar on Christianity, but I have dedicated some years to study Christian history, in the academy, in travels, in socializing, in political debates etc.
personally I find the line of thought that an 'outsider's' opinion is of no worth to be terrible, Christianity is not a big secret, it is the most common and perhaps most studied religion in history, many strong atheists and people of the academy have mastered the study of Christianity, and they can sure make professional and learned takes on Christianity, better than those of most priests who parrot the Hebrew scriptures in a foreign tongue.
It's like me telling you that the history of atheism is communist dictatorship because in terms of numbers and power Stalin's Russia and Mao's China fill the frame. Of course such a view is nonsensical. Much like defining Christianity by Rome
Sure if you want to go there, lets do it. Stalin and Mao have not executed mass murders against their own people in the name of atheism, they have done so in the name of the communist party, on the other hand Christian knights and soldiers marched into the lands of the east with a fierce religious zeal and conviction, with a declared purpose of liberating their holy sites.