You can refuse to offer a service to anyone you want as long as you are not exercising a Constitutional right

Opponents of Indiana's Religious Freedom Restoration Act argue that a business owner cannot use the Constitutional right of free religious exercise as a legitimate excuse to refuse service to someone.

Below are CafePress' "Guidelines for Prohibited Content":

• Content that may infringe on the rights of a third a party.
• Items that make inappropriate use of Nazi symbols and glamorize the actions of Hitler.
• Use of marks that signify hate towards another group of people.
• Hate and/or racist terms.
• Inappropriate content or nudity that is not artistic in nature.
• Content that exploits images or the likeness of minors.
• Obscene and vulgar comments and offensive remarks that harass, threaten, defame or abuse others such as F*** (Ethnic Group).
• Content that depicts violence, is obscene, abusive, fraudulent or threatening such as an image of a murder victim, morgue shots, promotion of suicide, etc.
• Content that glamorize the use of "hard core" illegal substance and drugs such as a person injecting a vial of a substance in their body.
• Material that is generally offensive or in bad taste, as determined by CafePress.com.

In other words, you can refuse to offer a service to anyone for any reason as long as your reason for doing so isn't an exercises of a Constitutional right.

Go figure.