If they hold themselves out to the public as providing the service -- they list themselves on the internet, or in the phone book or post a sign that says, "We cater weddings!", then it means, "We cater weddings!"
AFAIK there is no requirement (yet) that that the neighborhood baker, florist or photographer do weddings, but if they say that they do weddings, then it seems logical to think that it means that they do weddings.
BTW I have no doubt that what happened to Memories Pizza was a setup. The "reporter" must have asked the florist, and gotten the answer: "Sure, we'll take their money!", asked the baker, and gotten the answer: "Sure, we'll take their money!" and asked the photographer, and gotten the answer: "Sure, we'll take their money!"
They probably needed to go fairly far down the chain before they got someone to take the bait and got the answer they were looking for.
Who on earth has a wedding catered by a pizzeria????
You know that's not the case. If a muslim business refused, there would be no repercussions. If a black business were asked to server a klan rally and refused, there would be no repercussions. This is about forcing Christians to celebrate poop chute marriage.
Would it be okay for the same business to say ""We cater weddings between a man and a woman only!"?