Communies and Leftists always see the world as a zero sum game. They steal something from you to give it to someone else. If that can’t do that, then they prevent you from earning what they want to steal. In this case, it’s wedding receptions.
Of course, there’s another way to skin a cat; the owners could give an interview to a Baptist Sunday school paper declaring that they will continue to contribute to supposedly anti-gay marriage (actually pro-family) charities, then the homosexuals will boycott them.