That is not true. When the Pope writes an encyclical he doesn't necessarily have to name names. That way the timelessness of what hes says comes through. When he condemned the racial policies of the nαzι government what he said about the issue doesn't just apply to them. It also applies to us also.
In this case, you're wrong. Pius XI did not describe official NSDAP policy, but those within it that attempted to go a direction that the government policy never endorsed. Nothing more.
Think about it. The NSDAP policy was spelled out by 1933 when the Vatican backed there rise to power. Nothing changed between then and 1938. Just like there were those that were amongst the clergy prior to Vatican II that claimed to be Catholic that the Church warned about that was never Church policy, such as what Pius XI wrote about in Mortalium Animos.
You are just flat out wrong about this Poche.