Let him in and speak. If you don't want to listen to him don't. We have free speech in North American that in a lot of Europe is being limited to be PC.
There is an Islamic Extremist Andy Chaudry of the UK who wants to demonstrate out side the White House about how we infidels are going going to hell. He is the opposite of Gert Wilders. We are letting him in although I'm sure he in mourning at the moment as his Holy Warrior hero has passed beyond the Event Horizon.
It's free speech, ignore it if you want to but them speak. If they are kooks ignore them and they will go away.