Since this is clearly an “in your face” assault on Christian businessmen, I have an alternative:
DO A LOUSEY JOB! I highly-skilled photographer, for example, can skillfully time his shots to make the subject look, sick, drunk, ugly, etc.
As for a caterer, it might be hard to louse up a cake (salt vs. sugar?)—but think what could be done to salads and hors d’oeuvres!!
They are creative—so get with it and retaliate.
I would get all money up front and make them very nervous to seve the food to any guests.