Expressing free speech but scaring off customers?

There’s a great conversation going on in the comments section of a story about a mural on the back of a computer repair business in the Fan.

It raises a fascinating topic: When and how should business owners express their personal views. How do you perform a cost/benefit: You may lose customers who disagree – but what do you gain? Perhaps personal satisfaction? And how do you calculate or measure that?

This same topic also comes up this time of year when companies promote their charity of choice. It seems to me that they should just stick with selling whatever it is they sell, and let customers donate to causes of their own choosing.