The point was that it isn't that simple.

Let me try to make the point in a another way.

Let's say a gay person asks her to create a website for their friends "normal" marriage, she is fine with it and takes their money. She didn't discriminate against their sexuality, she rendered the service to a gay person just fine, the difference is the product.

Now let's flip it, a straight person askes her to create a website for their gay friends wedding. She now has refused service based on the product sold.

The question the court needs to answer where is the line drawn, they have chosen it. Religion is also protected, racism has no religious base, what is deemed marriage is.

The argument to be made is that she does not believe that marriage between gay people is right and she refused service on those grounds, whether asked by either sexuality.

This is all hypothetical but the point is the argument isn't trivial, how you frame it makes a big difference.