Because the group was founded and led by a Nazi in 1951 who believed in the exact same thing as the Nazi party but wasn't a member, therefore avoiding pretty much any and all consequences.
Here's a snippet from a book I randomly happen to own a PDF copy of about him:
Rough translation:
Unharmed, the Nordic Faith Community of Wilhelm Kusserow survived the denazification because he wasn't a member of the Nazi party. Additionally, he managed to be perceived as a victim by authorities, thereby avoiding post-war reeducation in interment camps. Afterwards he founded the Artgemeinschaft e.V. [rest of name] which adopted almost the same creed as the former Nordic Faith Community.
But not a single thing more than one or two.
Because the group was founded and led by a Nazi in 1951 who believed in the exact same thing as the Nazi party but wasn't a member, therefore avoiding pretty much any and all consequences.
I don't think it was possible to be an SS member and not also be member of the NSDAP. Be that as it, may, same difference anyways.
Here's a snippet from a book I randomly happen to own a PDF copy of about him:
Rough translation: