I think you are mistaken because when you buy from a vendor selling meat that has been sacrificed to idols you are choosing to support what they are doing with your hard-earned cash and you are essentially subsidizing the worship of other gods. When a gay person buys a wedding cake from you they are subsidizing whatever you are into, and in the case of Christians that is the Church, particularly if they donate all proceeds.
Paul’s concern in the meat offered to idols controversy was the cost it could have to a weak conscience, i.e., some Christian who couldn’t get past the idea it was just meat and the idols were nothing. For Paul, it was more important to protect the conscience of one for whom Christ died than it was to have access to that meat.
Likewise, a cake is just a cake, and nothing wrong with people eating it, here there or anywhere. But as long as gay “weddings” are essentially a form of attacking and denigrating the institution God gave us, anyone participating in such, while they may be able to live with it within their own conscience, must also consider the consciences of all who would remain faithful to Christ.
I originally thought something like this might be a good idea, and there are ways to do this that are so aggressively Christian it might even be effective, like providing totally Christianized catering to all customers without distinction. But at the end of the day, if someone in the back row of the church who isn’t as “sophisticated” as you spiritually sees this, and thinks it means you are sanctioning gay marriage, and follows what he thinks is your lead into that acceptance, you’ve tripped the wire of offending Christ in the matter. Better to stand and fight that to let your “cleverness” contribute to the downfall of a fellow believer.
Peace,
SR