You are hiring a babysitter. You can choose between a teenage girl who has no babysitting experience, or a paroled child molester who was a kindergarten teacher for 5 years. Is it discrimination to choose the less qualified candidate?
Yes. And the right to discriminate is a basic necessity of human interaction. It is about ensuring both parties in any interaction have given consent.
Okay, that was an extreme example. But what if KKK members came to the black owners of a clothing company, and forced them to make their robes? That is more reminiscent of the latest gay customer discrimination case.
A t-shirt printing company refused to print shirts for a gay pride event, citing religious beliefs. Actually, this happened five years ago, and another court just affirmed that the business does not have to provide services in this case because the owners objected to spreading the message of the group: gay pride.
This differs from the gay cake baking and flower arranging cases because in those instances the business owners were not objecting to spreading a message, but the actual behavior of the gay customers. So this case isn't really a victory for consensual interactions, it is just a technicality.
Interactions should require consent on the part of all parties. The business owner should not be forced to provide services just as the customer is not forced to buy them (unless compelled by government, but that is another issue).
Just reverse the situation and anyone can see that the right to discriminate is necessary. What if the Westboro Baptist Church went into a gay t-shirt maker's business and demanded 100 shirts that say "God hates fags." Should they be forced to comply, or are they allowed to discriminate?
Making moral distinctions between what type of discrimination is okay will change with the time, place, and attitudes of the population.
The citizens, local, and state governments in various places and times throughout the country would absolutely support forcing the gay business owners to print anti-gay shirts. We shouldn't have to depend on the majority to agree with us in order to exercise our right to discriminate. No one should be forced to do something without their consent.
The article explaining the case goes through the issue complaining the whole time that the shirts weren't even promoting being gay, they were just acknowledging it.
But this is entirely beside the point. Having KKK cloaks made wouldn't be promoting racism, just acknowledging it.