Those people would be immigrating to and respect that they are given the right to practice their religion as long as it doesn't infringe upon the rights or security of the people of the country.

I don't necessarily agree that it has to be the way you describe but I do suspect SOME immigrated with the idea of undoing us (like Omar Bakri Muhammed). At the same time, our laws should not be bending over backwards for those who commit treason and this is both a political and legal problem.