While we usually associate the Civil Rights Act of 1964
with racial discrimination, it clearly encompasses religious discrimination.
"The Civil Rights Act of 1964 prohibits discrimination on the basis of race, color, religion, sex
or national origin. "
Quote taken from:
Based on this, I don't see how it is legal for a business owner to refuse service to a person (or an organization)
based on that person's (or organization's) religious beliefs.