You are quite right.
But the immigration into England was never "unchecked." It was planned by the British government because they had a labour shortage, needed to rebuild their country after WWII, and had created their own obligations by making many muslim areas part of their empire. It was not like these people were coming from countries that had not been subject to British rule. They were, many of them British subjects, subject to the same Crown I was (am). There was very little "kindness" about the British policy as many people of colour and muslims were not at all well treated when they came to England, through programs designed to attract them.
I have spent most of my professional life being credentialed and in dealing with the Islamic world. I don't begin to claim I have the last word on the subject - but would argue no other Westerner does either.
I have found much to admire in Islamic culture. Cultural generosity can be almost embarrassing. Traditional Islamic arts in their purist form have almost no corollary in the West. You do not have to travel to the Middle East to experience it. Next time you are in Spain spend some time in the Al Hambra in Granada. My Arabic is still good enough to read and appreciate Arabic poetry and particularly Persian poetry translated into Arabic. I have dealt and negotiated with Arab and Pakistani military, political, and business leaders - in Arabic with those who were Arab. I have had Arab neighbors in places like Riyadh and spent extensive time in every Gulf country but Iran and Syria.
So allow me a couple of very general observations made over a lifetime developing them. I hasten to add general observations are just that and often untrue when applied to the specific - but that makes them no less generally true.
Muslims are not just like us. It is naive to believe they could be. Unlike the Irish, or the Chinese, or Africans, Islam itself creates enormous barriers to assimilation in Western Culture.
Our culture, and our understanding of the role of religion in it were shaped by two great interrelated events. The first was the reformation, and the second was the enlightenment. One, once a century and a half of warfare ended, created broad acceptable avenues to observe Christianity. The other threw open the doors of scientific inquiry free from the chains of religious orthodoxy. Finally, both largely destroyed the concept of submission to the will of God to the extent it existed in Christian culture.
As a result, in the contemporary West, one can be a "good Christian" and yet follow a host of acceptable personal mores different from one's neighbors. Those loving ritual have the Catholic and Episcopalian traditions, Calvinists find a home among Presbyterians, those wanting an emotional relationship with God choose evangelical congregations, and many others. All are "good Christians."
Even the Jewish faith experienced a slightly later reform movement. A member of a reform synagogue can enjoy a pulled pork sandwich on the deck with his Methodist neighbor, while his traditional cousin is adhering strictly to the traditions of halakhah and will not anything not prepared in a kosher kitchen. And yet, both can be "good" Jews.
Islam, on the other hand, has never had a reformation or experienced a lasting cultural enlightenment. A Muslim can only be a "good" Muslim by following the traditions of the religion and through submission to the will of God. That does not mean a Muslim can not be secular, but it does mean that it is almost impossible for a secular Muslim to be deemed living as a "good" Muslim by the Imamate.
Some secular Muslims spin the Islamic exception for those whishing to avoid persecution as support for secularism. Traditionally Islam views the world as divided between the "Dar al Harb" and "Dar al Islam." The "World of Islam" is self explanatory. The "World of War or Conflict" is that which Islam is still battling to convert. During that war, Muslims in the area of conflict may adapt local mores to escape persecution. But, that is hardly the basis for a stable secular existence in the West.
Generally, the lower the economic and educational status of a Muslim the more likely he or she is to cling to the stricter traditions of their faith. A sophisticated technocrat from Dubai is very different from a herdsman from Somalia or shopkeeper from Sanaa. It is why refugee enclaves in Detroit, Paris, or Ontario are very different than Italian of Irish neighborhoods the West has experienced with other migrations. I am convinced this lack of a real religious home for the secular Muslim is why so many children of these families become susceptible to radicalization by ISIS and its ilk.
Perhaps those in the West will eventually find a path for assimilation into our culture. I am afraid, however, that will be a long and all to frequently bitter process.
