Why do muslims find it so difficult to intergrate into english culture?

I can't speak specifically about England, but one of the major problems for them in the United States is our stance on religion vs. government, or separation between church and state. For the Muslim, this makes no sense (and truthfully, Christians would agree on this point). All facets of life are based upon your worldview, and if your worldview begins with Allah and the Q'uran, it doesn't stop at the voting booth. They create their own society from within, when the establishment (government) will now allow control from that end.