I believe the point is that she would also refuse to create a same-sex wedding site for a hetero customer and would be willing to make a hetero wedding site for a same-sex customer. It's a subtle but important distinction.
Of course, it gets very messy because in the case of wedding sites, the correlation between content and customer is 0.999999999.
Of course, it gets very messy because in the case of wedding sites, the correlation between content and customer is 0.999999999.