Would legally requiring the Ku Klux Klan /Nazis to allow minority members to join, help dismantle hate groups?

In the UK the BNP have been ordered to allow none whites too become members by a court, they were suppose to hold a EGM by today, which has been posponed. Their Leader Nick griffin said he was in a 'do or die' position as the court would have made them an illegal political group. So we shall see what if any effect the changes will make, I can't see anyone black wanting to join the KKK tbh. Though if enough join they could force an election and get one of their own in as grand master or even better shut them down.