Liberal values simply do not work when you start accommodating people that are aggressively illiberal. You have to be firm in defending your own values or they cease to be.
We don't sacrifice people on the top of a pyramid, we don't allow female genital mutilation, we don't throw people into the lion pits, and we shouldn't allow burkas. If you religion calls for one of these practices, it is time to reform once you are welcomed into Western Civilization.