I think we can't treat any demographic as a homogeneous mass, they will be as varied as any other ethnicity, if you take Jews for example, the Orthodox live in a more closed environment than say Reformed Jews who don't adhere to some of the strictures of their religion. So is the case with Muslims, Christians, they may loosely describe themselves as such, it's their cultural identity but that's as far as it goes in many cases.
I think the problem is, when any group of people don't want to assimilate or fight against the way of life of the country they have chosen to settle in, even more so should their brand of religion be a proselytizing one where the overall objectives are in conflict with ideals that we in the west believe in. Equality between the sexes and respecting same sex partnerships are both fundamental core beliefs, we can't go back to a time when those didn't exist. There are some Muslim countries that have regimes that are absolutely abhorrent why would we want to import any of that here to the west. Someone mentioned up thread that firebrand Christians can also be threatening, well yes they can, but they are somewhat thin on the ground here and don't have the captive audience that they would in say some of the southern states of the US, I tend to think we are more secular than America. In any case, my opinion is that countries who have too much interference from theocracies whatever their persuasion tend to be backward and given most are patriarchal do nothing to further the cause of women, at the worst they seek to suppress them, indeed some Muslim countries and states are living the medieval life.
I do worry that we are becoming more intolerant as a society, for example the number of speakers that are no platformed at universities now is disquieting, are these not places where debate should take place. Into that mix we have so many Jewish students who now have to worry that their name or appearance will denote their Jewishness and make them a target of hate. For them it's not enough to just be neutral they have to affirm their political beliefs are in tune with the groundswell movement that seems to have taken over.