If we have to explain it to you, well . . .
They were told they couldn’t sell pork AFTER they bought it, not before.
I think what you are getting at, however, is that not being open on Sunday is some sort of a arbitrary religious stricture impeding business.
I’ll bet you there’s nothing in Chik-fil-a’s franchise agreement that prohibits being open on Sunday because of the Sabbath. This is indeed the case, that Church’s won’t sell pork because it does not comport with Sharia law.
http://www.chickfila.com/pressroom/downloads/fact_sheets/Closed_on_Sunday.pdf
It’s a franchise wide policy. Closed on Sunday.
I am not sure if the contract says "because of the Sabbath", but I would venture a wild guess that the franchise agreement does prohibit being open on Sunday.