One might argue, however, that a payment processor should be treated more like a medical or utilities company, rather than a private business. It's one thing for a coffee shop to tell people "We don't want to serve you."--it's quite a different thing for a hospital to tell someone, "We don't want to serve you."

Being able to take credit cards is not exactly life-and-death, but it certainly can be for a business. Especially since the average Joe can't exactly go start their own Credit Card company to make a pornography-friendly payment processor. The CC oligarchy is firmly entrenched.