I'd guess that anyone joining is still subject to the beliefs that are held by them.
In there own words from their own manual:
"To maintain forever white supremacy." "To maintain forever the God- given supremacy of the white race."
Source:
http://history.hanover.edu/courses/e...kkkmanual.html
In saying this would non white etc members would need to hold a belief that they are inferior to the white members?