The real question is not whether Hitler was sincere, but rather why his Christian audience responded favorably to this stuff. The problem is in the audience, not the demagogue.
Sure, some people responded favorably, others didn't. A lot of people forget that Hitler's party never get a majority of the popular vote. But all that's beside the point.
My point is simply to discourage people from engaging in this kind of nonsensical tactic of trying to paint Hitler devout Christian. It's just as stupid as trying to claim Darwinian theory leads to Hitlerism. Frankly, it's behavior worthy of a troll.
AT MOST, you could claim that Hitler's convoluted belief system contained some elements of Christianity. But it wasn't Christian by any reasonable definition of the word.