I believe they claim that the Ainu are Caucasian.
Ainu are a unique set of people that should be considered indigenous, since they relate to a group called Jomon, who were the hunter-gatherers in Japan, and makes up a certain section of the Japanese genetics, though not dominant. The Ainu are distinct genetically from the average Japanese.
But Jomon was only predominant in Japan
before "civilization." Hitler merely projected his racial bias by stating all complexity everywhere came from these hypothetical Aryans. An example is he believed the Mesopotamian civilization was built by Aryans, and then brown slaves came and mixed with them. Brown people reduced civilization. It's just racist nonsense.
These people, Jomon, and Ainu are actually not West-Eurasian related at all. Their phenotype might have been what conforms more with non-East Asiatic but they are genetically entirely East Eurasian. They're not closer to Europeans than modern Japanese.
I used these basal source samples to make things very clear:
It still prefers the ancestral northeast Asian drift that is the origin of all the Chinese, Japanese, and Koreans.
This is roughly an Ainu from Sakhalin:
Hitler had no idea about Jomon. Those people were long extinct. The Ainu were culturally non-advanced relative to the Yamamoto (the average Japanese). It is not intuitive to attribute the success of the Yamato to Ainu-related peoples if the Ainu are some bear-nature culture people that lived in the woods, similar to the Sami of Norway, oppressed and forcefully assimilated. Japanese complexity started with China contact and ancient Chinese-related geneflow. Before that, they were hunter-gatherers.
Hitler chalked every complexity to Aryan invention because his racist ignorant perceptions of the world did not let him imagine brown people to be the cause of much development of things that Europeans had to adopt.
You're giving those ignorants too much credit. They don't know what they're talking about.
. I'm guessing they accept the genders I resigned them to 
