Albinism was considered a genetic defect.

People sometimes take Aryanism to be the blind embrace of whiteness, blue eyes, and blond hair. It was not. While its scientific basis was non-existent, its approach to racial types was not "superficial." The idea was that "Nordic" genetics were genetically superior and were responsible for all of the significant contributions of Western culture. They understood (per the genetics of the day) that individual expression of such characteristics could be varied (hence Hitler's lack of blond hair, blue eyes, etc.). Their "ideal type" was seen as an average external representative of the desired gene pool, but not a blond adherence to the most superficial characteristics of it.

Their view of human population genetics was flawed, to be sure. But they weren't idiots. They had a complex understanding of human biology and human history. It was definitely a wrong one, but it was not a superficial set of beliefs. What makes eugenics, Aryanism/Nordicism, scientific racism, "racial hygiene," etc., so disturbing is that the people who believed and advocated it were often quite logical, quite rational, quite scientific. It is a testimony to the ability of the human mind, even a highly-ordered and well-trained one, to subscribe to very dangerous falsehoods.

For a detailed discussion of the German racial ideology, see Robert N. Proctor, Racial Hygiene: Medicine Under the Nazis (Harvard University Press, 1990).