They could change the sign a bit...
We are a family establishment. If you came here to do ANYTHING other than order off the menu, then we insist you leave and DO NOT come back.
NO EXCEPTIONS!
Then throw out a straight couple for breaking the rules.
I like your idea. I would go so far as to invite a few hetero couples who were regular customers to enjoy a free meal, with the understanding that they show inappropriate public displays of affection. I would then very publicly “throw them out,” thereby setting a precedent that would permit the same response if degenerates came in.
In other words, set them up the same way they set you up.
Or you could have a couple of customers “on call” who would show up and harrass the fags until they left. Of course, you would publicy admonish the “intolerant” customers, but since they did nothing but loudly express their opinions, your hands are tied.
Then there’s always the option of serving the queers “saliva and mucus-enhanced” entrees ...