Christians prefer to cohabit with their own ilk. When someone in Christian culture goes seeking a roommate they always specify that any applicants must also be Christians in order to be considered.
They presume that if their roommate is a Christian then they will be kind, considerate, and clean, not be messy, obnoxious, or crazy. And like many of us who have actually roomed with Christians before, they’ll just have to learn that lesson the hard way.