I agree with this completely. You just send them further underground.
There is no 'but' as people would have you believe here. But they are Nazis. But I don't agree with them. But they cause riots and violence. There's always a 'but'.
Only a court order should have the power to shut these sites down and that's only if they present a clear and present danger.
This is clearly a cultural cleansing of sorts. I remember other such cultural revolutions. China comes to mind.