It would easy to simply 'not offer Halal Certifications' anymore. If a person has a superstition that they have to eat meat that has to be tortured first... they just have to go without then, just like say a cannibal has to 'go without'. If they 'BREAK the LAW' and torture an animal, then they go to gaol.
Peoples "freedom religion" doesn't extend past people "freedom from religion" and the Law.
