I do not think businesses should be “allowed to refuse gays” at all. Ridiculous. That would be like refusing left handers or Japanese.
1. On religious grounds, businesses should be able to refuse activity that is prohibited by their beliefs. Meaning if a clearly gay couple came into the bakery and wanted to buy two pink sprinkled cupcakes, you can’t refuse to sell them. But if they wanted you to help with their wedding party, you may refuse.
2. Businesses may refuse to serve anyone at any time. But the reasons should be things like personal (the guy hit on my wife) or cleanliness (a street bum) or safety (a guy who seems drunk and violent). A business should NOT be allowed to keep refusing service to blacks or gays or Jews.
Look what they did to Memories Pizza and it doesn’t even offer catering I think