Are you asking if business should be allowed to specify “No Jews, No Hindus, No Muslims”?
If so, I’m actually inclined to say “Yes, they should”.
However, given the fact that people generally need to sleep every day and eat several times a day, I’m not going to be fanatical about enforcing that concept.
Buying a wedding cake (or hiring a photographer), on the other hand, is generally done infrequently and with a long lead-time, and plenty of opportunity to shop around for alternate suppliers if the first one you try doesn’t wish to provide the service you’re looking for.
Using the brute-force of government to mandate someone to participate in an activity they find abhorrent for religious reasons is a clear violation of the “...nor prohibiting the free exercise thereof...” clause of the First Amendment of the Constitution.
Would you support a law requiring all restaurants to maintain a kosher/halal kitchen so that devout Jews or Muslims could eat there?
Businesses should absolutely not be able to refuse service based on religion or skin color or because someone is homosexual. They should be and are allowed to refuse service based on behaviors, but not identities.