"Discrimination" seems to be an increasingly meaningless word. Treating people differently based on their superficial traits is bullshit and you're a terrible person if you do it, but people now use the word to cover non-superficial traits too, such as religion. A person's religion is their choice and far from a morally irrelevant choice at that. Since religions make claims about how people should act, obviously one religion can be morally better than another. And of course treating everyone "equally" is actually wrong if they're morally different. (Instead, we should treat everyone "according to the same rules".) So actually, it's not just acceptable but can even be admirable to refuse to do business with someone based on their religion, if you believe their religion is morally repulsive.
Ideology is the only actually good basis for discrimination, but there are some others that are often treated as equivalent to totally baseless ones like racism and sexism, but aren't; namely sexual orientation and gender identity, because while feelings aren't necessarily a choice, actually having sex or asking other people to change the words they use is. If something is a choice, it can be criticized. And I'm not even saying that these choices are wrong, just that it's possible to sincerely believe they're wrong (and most of their critics do sincerely believe it and have understandable reasons), whereas there's no way to sincerely believe that being a different ethnicity is wrong.