Certain groups of people make a libertarian society impossible because they don't believe in private property norms. Extending private property norms to people who don't believe in them is not the moral high ground. They can't reject private property norms and then appeal to them in their own defense after they violate them. There is nothing wrong with removing these people because their only grounds for objection is norms they already rejected.
If you want to call that fascism, fine. I'd rather be a fascist than a double-speaking communist who extends the protection of private property norms to people who don't reciprocate.
This article isn't about anarchy and your concerns about where the division of labor lead aren't an argument against white people having their own communities. I could just as easily say that anarchy leads to more mass violence than fascism.
One can not freely choose who to associate with if one is forced to include latecomers. This is common sense.