I think that many, like the Proud Boys, are overtly racist and misogynistic, and he certainly appeals to that type, but then also to the less overtly hateful person who just feels really, really uncomfortable at the thought of the hierarchy, which is so deeply entrenched, being flattened out. Because they only believe in zero-sum, they think it means that the former "bottom of the pyramid" will now be at the top and they will be at the bottom. They just can't envision a world that isn't pyramid shaped.