That's hardly definitive. People really should be more careful about throwing around these extreme labels; it completely dilutes their impact when you apply them on a whim.
Sure, it's second hand information, and the author may have had reasons to play up Thiel's dedication to the cause. But still, when white nationalists are calling him "fully enlightened" and having meetings with him it certainly suggests at best a willingness to work with an assist white nationalists to achieve his aims, which is bad enough.
Is Milo a white nationalist? I always thought he was just the Breitbart court jester. In any case, I don't agree with just discarding nuance in these discussions; "fully enlightened" could mean anything from his libertarianism to his support of Trump as a candidate.
Unless Thiel, or anyone else really, comes out with some statement on the superiority of whites or the need to get rid of non-whites, let's desist from rushing to slap these labels on them.