But they don't say that, and if they did, you certainly wouldn't need any new policies to ban them. There are the 8chan lunatics, but outside that there are a wide range of views on what the white nationalist end-goal is and how to achieve it.

I'm reminded of the Sargon v Richard Spencer debate here. Sargon's line of attack was essentially this: You advocate for an ethnostate, people will not react well to the non-violent policies you publicly advocate to bring this about, thus there will be violence, therefore your rhetoric is violent. Even if you approve this line of reasoning, you have to admit that it can be applied to any separatist movement anywhere in the world.