But there is no reason why you or I shouldn't express an opinion about it.
Sure.
But then on the other hand:
Suppose the guy had been coming to work with a button that says ABORTION IS REALLY AWESOME. Or some atheist button. Do you think you would be equally outraged if he were fired?
Now, I am not trying to allege hypocrisy here - that'd be cheap.
My point is: there's no civil rights issue involved (except under current law). There's no civil right (except as invented by leftists) to get hired.
So, somewhere out there, a store which sells products I rarely buy fires a guy belonging to a social majority I don't belong to. Probably not the most fair thing in the world, no. But there are far greater injustices, even in America, even inflicted on Christians.