St Paul said that Christians were to buy meat at the market and not ask questions as to where it came from.
If the butcher said “This is meat offered to idols” then they were not to buy it. They could not even go to a dinner if the host offered meat he said was “offered to idols”.
If you did, it is considered that you approve of the sacrifice to idols. Same for “Halal” meats, sacrificed to allah. Kosher is fine.
Same for a cake maker. If a sodomite buys a cake, that is fine. If a sodomite wants to buy a cake and declares it is for a homo “wedding”, it is wrong for you to sell it if it is against your conscience.
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.