Living a town with about 25% muslims mostly living in a parallel society.. It's the 2nd and 3rd generation in general. Their (grand)parents came decades ago. And a majority still prefers an archaic world view over western freedom and equality. Over 50% of the youth states that the Islam is more important than local laws.
So, your guess.
Is it? Religion has nothing to do with nations imo. Immigration in general doesn't equal immigration of people of a completely different cultural and religious background.
Look this is for
@86Rick, too:
Both sets of my grandparents were ethnic Greek immigrants who spoke no English when they got here: My dad's parents moved into a 'Greek ghetto' and my mom's parents moved into a Sephardi Jewish enclave. Both communities were exclusionary zones: they felt comfortable among what they knew, and Americans were happy with them going into those neighborhoods where WASPs didn't have to deal with ethnics: shades of Irish, Italian, immigrants all over again. Loss of identity is very threatening to an ethnic immigrant.
My dad had to go to Greek school on Saturdays (I never went) , and his family social environment was Greek--except for public schools. And that's pretty much where assimilation begins: some in first-gen Americans, some in second-gen, some in third-gen. but eventually kids get alienated from the old culture and go on their way.
My kids' assimilation came swiftly because I had left the 'mother-city', went into university systems for baccalaureate and advanced degrees, and married a woman who'd grown up on planet Southern California

My wife took it even further: when our twin sons were born, each had his own room, and we sent each to separate schools: the twins were not going to grow up, as my wife determined, to think of themselves as a pair but as individuals (she was a twin and didn't like it when others treated her as a 'halfsie'). Individuation takes time and effort. She spoke only the Greek swear words, curses, and phrases I taught her, because she didn't want not to understand what I was saying when I used the language. Also, we could swear in front of the kids
I still have to laugh when my wife, when a cop pulled her over, said 'your mother grabs her ankles for three-legged dogs'.
And going back to visit Greek parents and grandparents? I'll never forget flying back from a visit to my grandparents with my wife (who was yes, an outsider to both households) and she muttered under her breath as we got off the plane 'I want a fucking hamburger, fries and a shake, and whatever I fix for dinner tonight is gonna have Velveeta in it'. My kids weren't raised eating Greek food, my wife patiently learned to cook some of it--the dishes she liked. We did baptize, chrismate, and communicate our kids in the Greek Orthodox church, but we dropped out of that when our eldest son came out.: the church had no place for him, so our family had no place for the church. If the kids go back to church, that's their decision, and it probably won't be GrOrth. They are not nostalgic types.
It takes generations, Snakebyte, so don't be impatient. Wait until the kids you mention eat their first pulled-pork barbeque or get a mouthful of bangers and mash and find themselves making friends with and being attracted to others outside the faith/language community. Alienation from a mother-ethnic culture takes time, lots of time. I have at least three Muslim friends, one Pakistani, one Indian, and one Algerian who have shared similar feelings about growing out of a hide-bound ethnic culture. It does happen, it just takes time.
It doesn't help that we've elected a xenophobe. I'm minded of Ferdinand and Isabella expelling the Jews and breaking up El Andaluz, where three faiths had gotten along well together happily for quite some time. My mother's family was originally expelled as Jews from Toledo Spain and eventually ended up in Saloniki in Greece--but we are all Americans now and this is
our country.
Be patient.