You're claiming that the Nazi distribution of Die Botschaft Gottes requires us to define Hitler as not Christian?

Many Christian movements have issued minimized Bibles. In the 2nd century, Marcion's canon rejected the entire OT. In the 19th century, the Slave Bible removed the Exodus story.

You might disagree with such efforts but the people behind these modified Bibles are usually regarded as Christian, so I'm not seeing your argument.