Yes, I think business owners "should" be able to discriminate.
Commerce, like speech "should" be free. (i.e., We should be able to make any statement whether racist, sexist, ageist, homophobic, anti-religious, vulgar, or simply offensive.)
Barronelle Stultzman "should" be able to refuse service to someone who is gay, because she believes Jesus wants her to. She is also free to say (and she does) that "She has nothing against gays ... and it isn't personal." Who knows, business may even improve because of this. She's gotten a lot of free publicity, and those "in her corner" may become future customers.
But, there is also a young woman (Eryn Hugo) who also exercised her right in all this, and has my greatest admiration. After realizing that she could no longer work for a company that would refuse service to a customer of nine years due to their sexual orientation, she quit.
She, too, has convictions.
Too often we hear of people, who don't like their job, or do things at work they know are fundamentally wrong. They may lie, steal, falsify records (timecards), accept bribes (or campaign contributions), threaten others, pass the buck, leave behind pollutants or ecological damage, etc.
They do this not to keep their job, or to make a fair wage, but to simply get "more."
But, this is something you don't see every day, a person put their moral convictions ahead of their job. I sincerely wish Eryn the best of luck in finding her next job.
-- D. L. (ANDY) ANDERSON, Richland