Churches should have in their facilities policy a statement to the effect:
The church reserves the right to not host and/or to evict people whose actions and/or beliefs are contrary to the church’s spiritual tenets. The senior pastor and/or church administrator will make the decision at the time of the building use request.
You can get longer than that but this simple paragraph ensures the church is on record for saying “there are groups we don’t want in our building; we’re not going to define all of them here, but we reserve the right to make that decision when the time comes.”
That statement does not single out same sex marriages (in the news so much lately). You don’t want a statement singling out a specific group because there are too many to single out. Leave the decision-making authority with senior staff who will be more informed about everything and can make decisions more quickly. Even churches that are gay-friendly won’t allow some (legal) groups to meet in their buildings: neo-Nazis, KK Klans, political candidates, pedophiles anonymous, etc.
Caution: this policy does not absolve the church of any action which is, by law, discriminatory. The church must abide by the law. But I challenge the church to welcome people especially those who are not “like us.” Actually, that isn’t my challenge, that comes from Jesus. You don’t have to approve of their lifestyle (Jesus didn’t condone the actions of the Samaritan woman, but he did treat her civilly).
Don’t create a policy to exclude only one group. Be strategic in your policy-making.
Lead On!