If you're going to use their strategies (i.e. re-writing history to fit your pre-formed ideas) then you shouldn't be surprised if you get painted with the same brush.
Traditional Roman Catholic who, BTW, accepts evolution. The fact that Hitler said he was a Christian doesn't make him one, anymore than my saying I'm a brain surgeon makes me one.
However, he certainly would not be "anti-religious", which was how you phrased it. He was the exact opposite - he saw religion as an excuse for the very things he did. He specifically protected and promoted a religious faith, and both the Catholic and Protestant churches befitted greatly from his patronage. You may try to argue that he wasn't a Christian, but he thought he was, and the churches he honored didn't bother saying otherwise until after he was dead.
The others you listed killed in the name of communism, not "anti-religion". Nor did they preferentially target religious individuals. Pol pot killed most of his people through simply forcing an agrarian society, and executing anyone who disagreed.
Stalin killed indiscriminately, with many of his victims being communists (i.e. nominal atheists). Quite interestingly, Stalin himself may not have been an atheist; he was trained as a priest, and by some accounts maintained that faith throughout most/all of his life. He even re-opened churches in WWII, reversing much of the "anti-religious" activities of his predecessors.
Like Stalin, Mao killed indiscriminately. He targeted members of the old government, west-friendly individuals, competitors within his communist party, and the vast majority simply through his war and forced land reforms. Mao's cultural revolution, who's purpose was to destroy the last vestiges of the "liberal bourgeoisie, did target some religious organizations (while others enjoyed protection), but also targeted artists, party members and authors.
http://en.wikipedia.org/wiki/Bourgeoisie
As far as hospitals and universities, I will admit to a euro-centric perspective and plead ignorance as to the state of Chinese civilization. What the Greeks had were hardly universities in the sense we think of them now, although your point about education is well taken.
Actually, they are quite similar to what we have now, with most modern universities being structured along the same lines as the Greek ones (formally called academies). Even todays degree structure - bachelors, masters and doctorate, has its origins in the Greek academies. About the only difference today is scale and the separation into different faculties.
As for preserving civilization, there is an admirable book entitled "How the Irish Saved Civilization." Written by, I believe, an Irishman, though his name escapes me at the moment. Endorsed by me, another Irishman!
According to the book jacket, and the few reviews I read, the book claims the Irish preserved (and later re-spread to northern Europe) roman catholicism in the early days after the fall of the roman empire. Hardly saving western civilization, unless religion is all that our society is...
The fact of the matter is that evil, like goodness, has been committed by all manners of people. I am, however, relatively certain that religion has produced more of a positive record than negative,
I'd argue the opposite, but regardless...
and that the lack of religion has never had as healthy an effect on civilization as its lack.
I'd also argue the opposite here. Nearly all of the advances we attribute to modern society - development of technology, human rights, civil rights, universal suffrage, etc, all occurred first (and are largely restricted to) secular nations - by which I mean nations which hold that church and state are to be separate. In contrast, societies heavily dominated by religion, or where church and state are linked - the middle east and medieval europe as extreme cases - completely lack these traits.
Likewise, there is a well-established link between how religious a society is and how violent it is; with secular nations being less violent, having fewer teen pregnancies, fewer divorces, fewer std's, and so forth.
For example:
http://moses.creighton.edu/JRS/pdf/2005-11.pdf
As a scientist I can tell you that religion has had a horrendous effect on the progress of science, and continues to hamper scientific advance to this day.
Bryan