Most white supremacists are self identifying Christians, so yes. They are members of the christian cult of personality.

Otherwise, no. people will often throw around the word "cult" all willynilly and often apply it to situations that are not necessarily "correct", but aren't exactly wrong either. Like, for example, Hitler. I've often heard people identifying the Nazi party as a "cult of personality" BUT that's really just a way of hyperbolizing the reverence with which Hitler was treated by his underlings, it's not meant to be taken literally. I would say the same of white supremacy for the most part.

Now, if we're talking a 'dear leader' type situation like in North Korea where your leader is assigned a sort of 'supernatural' origin, you could probably make a pretty convincing argument for it being a cult.

hope that helps