Some of the ways one accommodates people who come from societies unfriendly to secular, liberal culture:
Along with everyone else,
1. Their children are required to go to public school and receive 12 years of training in the secular, liberal language, history, science, and civic institutions of the society.
2. Their young adults are liable for military service (unless physically unable)
3. Children, youth and adults may not impose their dietary restrictions on public kitchens
4. Children, youth, and adults may not engage in group religious rituals or wear specific religious clothing in public places (like schools, public institutions, public transit, etc.)
5. Standards accepted by the larger society in the area of dress or undress may not be challenged on a religious or specific basis. Don't like 95% of a body's skin exposed at beaches? Don't go there, then. Don't accept men and women sitting in the same whirlpool at the Y? Don't sit in the whirlpool, then.
6. Religious institutions (of all denominations) must fit into the surrounding community with respect to architectural styles, noise, outdoor events, and so on. Can the Holy Rollers open the windows and doors for their all night soul jam with highly amplified music and associated screaming? No. Can mosques broadcast the call to prayer 5 times a day hearable beyond 500 feet? No. Can a 4-spired big-domed box be built in an area with colonial era architecture? No.
7. Employees of private firms can not claim exemption from contact with unclean or holy meat. We eat pork and we kill sacred cows. Don't like it? Tough.
8. Apply anti-discrimination law (on the basis of gender) where applicable.
9. Expose everyone to non-stop commercial messaging about products, consumerism, pornography, etc.
These are not altogether new issues. Orthodox and ultra-orthodox Jews, Amish, Christian Scientists, Hutterites, Mennonites, Quakers, Jehovah Witnesses, and atheists have all contended with civil authorities to work out the details. Peace church members, for instance, may not have to undergo combat training and service when drafted, but they have to spend 2 years doing demanding public service work. Amish children do not attend high school in some states beyond the 8th grade. Amish travelers have to abide by rules of the road when moving about in horse-drawn vehicles (signaling, using large reflective triangles, even lights on their carriages and wagons.
Catholics and Lutherans may run their own elementary and secondary schools, but they are obligated to conform to the state mandated curriculum guidelines. (Of course, when the state itself is ready to approve creationism, then what?)
As painful and difficult as it has been (the suffering is incalculable) Americans, for instances, have learned to live with the weird clothing of ultra-orthodox Jews, Traditional Amish, Hari-Krishna pan handlers and flower children (a couple of generations back) and so on. Americans have somehow learned to eat Lebanese, Greek, African, Vietnamese, and South American food. (The only kind of ethnic food restaurants missing in Minnesota are Norwegian, German, and Swedish. Strange. You would think in a place that is 60% NW European, there'd be more places serving sauerbraten, lefsa, pickled herring, liver dumplings, and such. If it wasn't for IKEA, there'd be no place to get Swedish meatballs with lingonberries.)