I personally believe anyone should be able to refuse to sell to, or do business with, anyone for any reason. Trying to restrict that is only going to cause them to come up with any other reason they can think of to say no.
If an old-timey southern restaurant owner wants to refuse to serve "coloreds", he should be able to do so. If a car salesman, or this photographer insists on doing business with a woman's husband and never with her, they should be able to do so. The consequence for doing something like this which the community abhors should be boycotts, losing business, bad publicity, etc. (exception: if you provide some kind of vital service important to public health like a pharmacy or hospital, you don't get that kind of leeway)
However, if we are going to have laws that say a public business is not allowed to refuse service to protected classes, and if minority races and women are considered protected classes, then I don't think this case be an exception at all. Either a business should be able to refuse to do business with any race, gender, or sexual orientation, or they shouldn't be able to refuse any of them.
<ptp> how many emo kids does it take to change a lightbulb?
<Willy> HOW MANY?!
<ptp> none they just sit in the dark and cry