The baker didn’t refuse to bake the cake, she refused to put the message on it that he wanted and offered him the materials needed to put it on there himself.
Although those involved won’t say at this point, I’ll wager what he wanted put on the cake was a scripture verse. In time we will know for certain.
She refused to provide the cake he wanted to order.
Unless the Republicans in the state legislature have their way, in time she will be driven out of business for her actions.