As an adult, Hitler specifically rejected the Catholic Church, as well as Christianity in general. He described himself as "a complete pagan".
The book Hitler's Secret Conversations: 1941-1944, published by Farrar, Straus and Young, Inc. (1953), contains definitive proof of Hitler's real views. The book was published in Britain under the title, Hitler's Table Talk: 1941-1944, which title was used for the Oxford University Press paperback edition in the United States.
All of these are quotes from Adolf Hitler:
Night of 11th-12th July, 1941:
National Socialism and religion cannot exist together.... The heaviest blow that ever struck humanity was the coming of Christianity. Bolshevism is Christianity's illegitimate child. Both are inventions of the Jew. The deliberate lie in the matter of religion was introduced into the world by Christianity.... Let it not be said that Christianity brought man the life of the soul, for that evolution was in the natural order of things. (p 6 & 7)
10th October, 1941, midday:
Christianity is a rebellion against natural law, a protest against nature. Taken to its logical extreme, Christianity would mean the systematic cultivation of the human failure. (p 43)
14th October, 1941, midday:
The best thing is to let Christianity die a natural death.... When understanding of the universe has become widespread... Christian doctrine will be convicted of absurdity.... Christianity has reached the peak of absurdity.... And that's why someday its structure will collapse.... ...the only way to get rid of Christianity is to allow it to die little by little.... Christianity [is] the liar.... We'll see to it that the Churches cannot spread abroad teachings in conflict with the interests of the State. (p 49-52)
19th October, 1941, night:
The reason why the ancient world was so pure, light and serene was that it knew nothing of the two great scourges: the pox and Christianity.
21st October, 1941, midday:
Originally, Christianity was merely an incarnation of Bolshevism, the destroyer.... The decisive falsification of Jesus' doctrine was the work of St. Paul. He gave himself to this work... for the purposes of personal exploitation.... Didn't the world see, carried on right into the Middle Ages, the same old system of martyrs, tortures, faggots? Of old, it was in the name of Christianity. Today, it's in the name of Bolshevism. Yesterday the instigator was Saul: the instigator today, Mardochai. Saul was changed into St. Paul, and Mardochai into Karl Marx. By exterminating this pest, we shall do humanity a service of which our soldiers can have no idea. (p 63-65)
13th December, 1941, midnight:
Christianity is an invention of sick brains: one could imagine nothing more senseless, nor any more indecent way of turning the idea of the Godhead into a mockery.... [here he insults people who believe transubstantiation] .... When all is said, we have no reason to wish that the Italians and Spaniards should free themselves from the drug of Christianity. Let's be the only people who are immunised against the disease. (p 118 & 119)
14th December, 1941, midday:
Kerrl, with noblest of intentions, wanted to attempt a synthesis between National Socialism and Christianity. I don't believe the thing's possible, and I see the obstacle in Christianity itself.... Pure Christianity-- the Christianity of the catacombs-- is concerned with translating Christian doctrine into facts. It leads quite simply to the annihilation of mankind. It is merely whole-hearted Bolshevism, under a tinsel of metaphysics. (p 119 & 120)
9th April, 1942, dinner:
There is something very unhealthy about Christianity (p 339)
27th February, 1942, midday:
It would always be disagreeable for me to go down to posterity as a man who made concessions in this field. I realize that man, in his imperfection, can commit innumerable errors-- but to devote myself deliberately to errors, that is something I cannot do. I shall never come personally to terms with the Christian lie. Our epoch Uin the next 200 yearse will certainly see the end of the disease of Christianity.... My regret will have been that I couldn't... behold its demise." (p 278)
The conference of German bishops excommunicated all Nazis in 1930, and in the 1932 elections forbade Catholics to vote for a Nazi. By being the leader of the Nazi party, Hitler had already put himself outside of the Church.
Finally, it should be noted that the whole purpose of excommunication is to help the sinner recognize the enormity of his sins, so he will seek forgiveness. As St. Paul wrote: "If any one refuses to obey our word by this letter, note that man, and have nothing to do with him, that he may be ashamed. Do not look on him as an enemy, but warn him as a brother." (2 Thes 3:14-15). Someone like Hitler, who did not believe in the truth of Christianity, would simply shrug it off.
Those Hitler quotes sound like the current atheists, are you sure these are not urban myth?
SovietProfessor does not let facts get in the way of a good rant against religion (well, Christians anyway). Besides, an atheist is yet again trying to impose his views on others, so a distraction was needed by one of his peers.