To be fair (or play devil's advocate), making an association between those of a Paulish creed and white-supremacist groups is somewhat like labelling Democrats as Communists. Despite the falsehood of that claim with regard to most Democrats, it happens quite a bit around here. It is nonsensical to try to demonstrate that Democrats by and large are not Communists on this board simply because such a sentiment is drowned out so quickly by vociferous and extremely hostile claims to the contrary.
However, when groups like those to which the OP refers make such statements of support, I would think that at a minimum, it only would benefit the Paul campaign and his more mainstream - or at least inclusive - supporters to disassociate publicly from those groups, unless by silence acceptance of that support is to be inferred.