I'm pretty sure I did know that as checked the Supreme Court decision while working on my comment, and it says https://www.supremecourt.gov/opinions/17pdf/16-111_j4el.pdf
> Masterpiece Cakeshop, Ltd., is a Colorado bakery owned and operated by Jack Phillips, an expert baker and devout Christian. In 2012 he told a same-sex couple that he would not create a cake for their wedding celebration because of his religious opposition to same-sex marriages—marriages that Colorado did not then recognize—but that he would sell them other baked goods, e.g., birthday cakes.
In my comment I removed text where I quoted from the decision, as there's no way that decision can be discussed in the sort of off-handed way that jpxw brought it up.
Also, I didn't realize there were multiple relevant cake maker lawsuits, so perhaps jpxw could be more specific, as the Supreme Court decision doesn't seems to have a direct bearing on the topic, leaving the underlying issue in confusion.
Christian book stores can't exclude Hindus from buying their books. One upon a time they could, but that's now illegal.
There is no law saying Christian book stores must stock the Bhagavad Gita.
There's also no law saying Amazon must stock certain books. But there are laws preventing Amazon from excluding certain classes of people as clients.
To your question, the Supreme Court has said that lack of religious neutrality by the Colorado Civil Rights Commission was inappropriate, in such a way that the case should be overturned.