Both Hitler and Stalin were pragmatic politicians, ready and willing to overthrow ideological positions and personal prejudices whenever it would give them an edge. The history of the war is replete with power plays and unexpected alliances that shifted as conditions did.
A good reference for the early part of the war that goes into great detail on this is John Lucacs’ The Last European War, 1939-1941.
A further IIRC: there was a Japanese man who, sometime between the formation of the Axis and Pearl Harbor, who used this “science” to challenge the (racist) immigration quotas in the United States.
Perhaps I don’t RC.
In Ozawa v. U.S., it is the language described as “aryan,” and Japanese as “white” and “not Chinese.” Also, it was decided in 1922, long before there was an Axis, of course.
The core of Hitler’s program was the destruction of communism, at home and internationally. He believed that the Jews were responsible of Bolshivism. He was not alone in this belief. Reactionaries and counterrevolutionaries of various stripes worldwide believed it. Some still do, although it is rather a moot point.
So Hitler had no problem allying himself with whomever would serve his purpose at the time. It is important to recognize that it wasn’t Hitler alone who was interested in the destruction of the USSR. He was only one man. This had been a worldwide priority for capitalism from 1917 and remained so untill 1991 when it was ultimately successful.