"Whether anyone wants to believe it or not one of the tenets of Islam is to spread Islam wherever they migrate to."
Hmmmmm... seems like Christianity does the same thing...
So you think that anyone who is not Christian should leave America? That IS what he said by the way with respect to Australia (at least the quote presented here.) That is not the freedom that the so called "christian" founding fathers had in mind. And by the way, all because the founding fathers were christian (and not all of them were), doesn't mean the society and everyone in it has to be. That is not what they intended, contrary to popular opinion.
Some interesting reading:
Little-Known U.S. Document Proclaims America's Government is Secular - The Early America Review, Summer 1997