More on the Catholic position in evolution. This is JP2 from as recently as 1996, the first major update to the 1950 statement by Pius XII.

Before offering you several reflections that more specifically concern the subject of the origin of life and its evolution, I would like to remind you that the magisterium of the Church has already made pronouncements on these matters within the framework of her own competence. I will cite here two interventions. ...

The earlier cite is to the 1950 encyclical:

In his encyclical Humani Generis (1950), my predecessor Pius XII had already stated that there was no opposition between evolution and the doctrine of the faith about man and his vocation, ...

Note the "no opposition" wording.

Taking into account the state of scientific research at the time as well as of the requirements of theology, the encyclical Humani Generis considered the doctrine of "evolutionism" a serious hypothesis, worthy of investigation and in-depth study equal to that of the opposing hypothesis.

So the 1950 encyclical was luke-warm, merely saying that "evoluitionism" was "a serious hypothesis, worthy of investigation", but that its status was "equal to that of the opposing hypothesis".

"Today, almost half a century after the publication of the encyclical, new knowledge has led to the recognition of the theory of evolution as more than a hypothesis. ... It is indeed remarkable that this theory has been progressively accepted by researchers, following a series of discoveries in various fields of knowledge."

So that, as recently as 1996, was the first official Catholic acceptance of evolution as likely true. (Of course it didn't apply to our "spiritual souls", where were God-given and not evolved.) But anyway, this is all way after Hitler's youth, when he would have been taught the traditional picture -- as believed by the vast majority of Christians until after WW2 -- that God created humans in their current form. And, as is clear from Mein Kampf, that is what Hitler believed. And as is clear from the above quotes from Houston Chamberlain, the Nazis explicitly rejected Darwinism, regarding it as an "English disease".