You are raising the same issue that was raised by Canadians when Muslims in a community were demanding that the school stop serving pork to their children.

The school principal with commendable integrity (that is missing from many of our school principals here) replied that there are many countries where Muslims can go where they would be able to set the rules but as long as they are in Canada, they must abide by the norms of Canada. End of story.

Why underpopulated? Have these Muslims been (par for the course) killing each other off for a lack of "infidels" to kill?

The other 57 may be ready to accept them (perhaps excluding Indonesia). but something tells me the distaste for secularism is outweighted by their like of the comforts they may obtain here and nowhere else.
It is a difficult struggle and perhaps what is disliked is the ease with which comforts overcome religious fervor.

Okay, I got all this out of my system!