You can deny it, but you cannot back it up. However, I can back up his statements:
I can indeed hardly see how anyone ought to wish Christianity to be true; for if so, the plain language of the text seems to show that the men who do not believe, and this would include My Father, Brother, and almost all my best frieds, will be everlastingly punished. And this is a damnable doctrine.
Further on he says:
A being so powerful and so full of knowledge as a God who could create the universe, is to our finite minds omnipotent and omniscient, and it revolts our understanding to suppose that his benevolence is not unbounded, for what advantage can there be in the sufferings of millions of lower animals throughout almost endless time.
From; Gertrude Himmelfarb, 'Darwin and the Darwinian Revolution' page 385, quoting from unpublished passages in the Autobiography.
That Darwin was totally dishonest about his religious views in public, there is tons of evidence:
Many years ago I was strongly adviced by a friend never to introduce anything about religion in my works, if I wished to advance science in England; and this led me not to consider the mutual bearings of the two subjects. Had I foreseen how much more liberal the world would become, I should perhaps have acted differently.
From: Gertrude Himmelfarb, 'Darwin and the Darwinian Revolution' page 383, quoting from the Cambridge manuscript.
Last night Dicey and Litchfield were talking about J. Stuart Mill's never expressing his religious convictions, as he was urged to do so by his father. Both agreed strongly that if he had done so, he would never have influenced the present age in the manner in which he has done. His books would not have been text books at Oxford, to take a weaker instance. Lyell is most firmly convinced that he has shaken the faith in the Deluge far more efficiently by never having said a word against the Bible, than if he had acted otherwise.
...
I have lately read Morley's Life of Voltaire and he insists strongly that direct attacks on Christianity (even when written with the wonderful force and vigor of Voltaire) produce little permanent effect; real good seems only to follow the slow and silent side attacks.
From: Gertrude Himmelfarb, 'Darwin and the Darwinian Revolution' page 387, quoting from the Cambridge manuscript.
"P.S. Would you advise me to tell Murray [his publisher] that my book is not more un-orthodox than the subject makes inevitable. That I do not discuss the origin of man. That I do not bring in any discussion about Genesis, &c, &c., and only give facts, and such conclusions from them as seem to me fair.
Or had I better say nothing to Murray, and assume that he cannot object to this much unorthodoxy, which in fact is not more than any Geological Treatise which runs sharp counter to Genesis."
From: Daniel J. Boorstein, The Discoverers, page 475.
You can deny it, but you cannot back it up. However, I can back up his statements
Well then why in the $&*(@# don't you?! How absolutely typical that nothing you posted had a damned thing to do with the question of whether evolution and creation are mutually exclusive and mutually exhaustive possibilities. Why don't you try to defend that?
The rest we've gone over before. Once again the fact (which I was quite aware of, and have acknowledged all along) that Darwin eventually abandoned his belief in Christianity (which he still held, however, when he first forumlated his theory) is irrelevant. Being a non-Christian is NOT equivalent to being an "atheist".
I'm also quite aware of Darwin's circumspection regarding public airing of his religious beliefs. It is entirely YOUR eccentricity to deny Darwin any right of privacy or reserve in this matter, and therefore brand him as "dishonest." It is crystal clear who the "dishonest" party is here.
I will grant, as I always have, that part of the reason Darwin was reluctant (on most, but not all occassions) to air his more skeptical religious views was to protect his reputation as a gentlemen, but there were other reasons as well, including to protect others. I don't mean just his family (esp his wife and sisters who were devout) though that was part of it. In truth Darwin was a mild-mannered type who disliked controversy, and didn't want to gratuitously oppress the religious views of others.
There is also the fact that Darwin, though he had his opinions, did not consider them to be authoritative. He tended to consider questions of ultimate origin, of the relationship between God and the world, and the like, to be, in all probability, insoluble. He certainly did not believe that he had solved them. Why then should he make make public pronouncements on matters that he himself considered to be little better than a muddle? Here are some of his comments along this line (from an 1860 letter to the American botanist Asa Gray with whom he often discussed these issues). Emphasis added:
With respect to the theological view of the question. This is always painful to me. I am bewildered. I had no intention to write atheistically. But I own that I cannot see as plainly as others do, and as I should wish to do, evidence of design and beneficence on all sides of us. There seems to me too much misery in the world. [examples snipped] On the other hand, I cannot anyhow be contented to view this wonderful universe, and especially the nature of man, and to conclude that everything is the result of brute force. I am inclined to look at every thing as resulting from designed laws, with the details, whether good or bad, left to the working out of what we may call chance. Not that this notion at all satisfies me. I feel most deeply that the whole subject is too profound for the human intellect. A dog might as well speculate on the mind of Newton. Let each man hope and believe what he can. Certainly I agree with you that my views are not at all necessarily atheistical. The lightning kills a man, whether a good one or bad one, owing to the excessively complex action of natural laws. A child (who may turn out an idiot) is born by the action of even more complex laws, and I can see no reason why a man, or other animal, may not have been aboriginally produced by other laws, and that all these laws may have been expressly designed by an omniscient Creator, who foresaw every future event and consequence. But the more I think the more bewildered I become; as indeed I probably have shown by this letter.
(If you want to read the full letter, click here and search for "remittance of 22 pounds".)
On the other hand Darwin did express his religious skepticism on a number of occasions, while still making it clear that he did not seek or wish to convince others. Here is a passage from Life and Letters (by his son Francis) that quotes from some of his correspondence with those inquiring about his religious beliefs. The emphasis again is mine:
Again in 1879 he was applied to by a German student, in a similar manner. The letter was answered by a member of my father's family, who wrote:—"Mr. Darwin begs me to say that he receives so many letters, that he cannot answer them all.
"He considers that the theory of Evolution is quite compatible with the belief in a God; but that you must remember that different persons have different definitions of what they mean by God."
This, however, did not satisfy the German youth, who again wrote to my father, and received from him the following reply:—
"I am much engaged, an old man, and out of health, and I cannot spare time to answer your questions fully,—nor indeed can they be answered. Science has nothing to do with Christ, except in so far as the habit of scientific research makes a man cautious in admitting evidence. For myself, I do not believe that there ever has been any revelation. As for a future life, every man must judge for himself between conflicting vague probabilities."