98% of the citizens of Germany at the time of the Nazi's were in fact self-identified as Christian.
And yes, just as numerous of those badges and symbols recognize, the vast majority of what was undertaken in Germany to rid itself of jews, non-christians and other "undesirables" was most certainly done in the name of Christianity.
The notion that you can deny they were Christians, as put forth is a variation of the logical fallacy known as: "No true Scotsman."
The damned motto of the country and there military was "God is with Us"
The 24th point of the Nazi party (their party platform) read as follows: "We demand the freedom of religion in the Reich so long as they do not endanger the position of the state or adversely affect the moral standards of the German race. As such the Party represents a positively Christian position without binding itself to one particular faith." (In other words, the party promised to protect the religious freedom of the people. so long as those people were Christian.)
The treaty "concordant" with the Catholic Church which Hitler signed in 1933 reads in part: "Catholic religious instruction in elementary, senior, secondary and vocational schools constitutes a regular portion of the curriculum, and is to be taught in accordance with the principles of the Catholic Church. In religious instruction, special care will be taken to inculcate patriotic, civic and social consciousness and sense of duty in the spirit of the Christian Faith and the moral code, precisely as in the case of other subjects." (In other words, Church and State were to be combined to a large degree as the Catholic church was obligated to teach nazi based patriotism as part of its educational system.
I think it's largely "denial" that keeps most from accepting that a "Christian" country and it's predominantly Christian populace undertook horrific things, while many Christian leaders of the country continually proclaimed it to be "God's will" and placed a belief that Gad was their side (and backed their actions) played a huge roll in what happened in the Holocaust.
http://www.ushmm.org/wlc/en/article.php?ModuleId=10005206
http://www.nobeliefs.com/Hitler1.htm
If the identical thing were to happen today, and it was the current Government of Iran who was behind it, I don't think a single person here would hesitate to couple the religious stances of the government of Iran and the overwhelming religious beliefs of a majority of Iranians who participated in such events and put blame on Islam. (And for good reason) Why then can you claim that there is some wide gulf between what that Nazi's and their followers (an overwhelmingly Christian group) did, which they publicly claimed was connected to their religious beliefs and the Christian religion, when they themselves believed to belong to both groups?