Richard Spencer has openly declared his White Nationalist aspirations, and is on video exhorting his supporters to party like it's 1933 and exchanging nazi salutes with them, with arguments like 'for us, it is conquer or die.'

You can see some highlights(>!) of a recent speech here: https://www.youtube.com/watch?v=1o6-bi3jlxk

I did not decide he was a nazi by making some theoretical extrapolation using Marxist calculus or somesuch. He's saying in plain English (and occasionally German) that he wants to engage in a race-based war of conquest in which the stakes are life and death.