If GE is true, this means that any change after the first of a “kind” is a degradative step towards extinction.
So if Adam was blond, any of his descendants that had brown hair would be imperfect and degraded.
Sanford is not the first person, of course, to pursue an ideology in which all human variation can be seen in terms of who is more or less “degraded.”. It has has quite a lengthy, if deplorable, history.