These white supremacists are trying to ride the coattails of the conservative movement and mainstream themselves. They seem to be convincing a lot of people.
The conservative movement failed. That is why we have the Weimerica that is leading to the reaction you fear.
They are not riding the coattails of the conservative movement they are replacing it.
Trump, who is obviously not Alt-Right, was still a repudiation of Conservatism Inc. He was fought viciously by the entire conservative establishment.
Trump promised no wars, reduced immigration, and to preserve Social Security. This is the opposite of Paul Ryan and crew.
Trump is not alt-right but he is most surely not Conservatism Inc either.