I’m sorry if it hurts, but Hitler was a Christian, and you can’t say his own words don’t matter because a quote is from a few years before he took power.
Do his words and actions which contradict that after he took power not matter by comparison?
Hitler was only a Christian insofar as he revered a figure called Jesus Christ to some degree. That he rejected nearly every common theological thread of Christianity, from Biblical authority, to the divinity of Christ, to the authority of any church, to questions of salvation of the soul, to pacifism, to Jesus's very existence as a Jew, should very much cast into question any characterization of Hitler as a Christian in any serious sense.