If they haven’t committed a crime, leave them alone.
The real purpose will show itself by labeling anyone/organization they don’t like, “white supremacists” and with a little help from the SPLC, BAM! A new class of citizen that can be harassed & harangued for fame, fortune & power.
That really is exactly how I see it. I was just having fun with the whole idea of banning organizations that don’t really exist in any “real” form.