What can my daughter do about an employer who has fired her because "she wasn't Christian enough"?

My college-age daughter works as a groomer while in school. She just went full time at a dog groomer where she was previously employed as an independent contractor part time. The owner has never given her negative feedback and she encouraged my daughter to go full time at her shop. Today, the same owner fired her saying verbally that she wasn't Christian enough. Apparently, this happened before and a complaint was filed with the BBB. The BBB plans to call the owner to give a warning or feedback but since my daughter has only been a full-time employee for a short time the BBB says there's not much they can do. Is there anything further that can be done? My daughter is upset about being fired. She's never had that happen before. I am frustrated that using religious affiliation (or presumed moral character/behavior) can be used by any employer as grounds for dismissal. Had she behaved unprofessionally and been reprimanded that is one thing but she had no warning. Thank you for feedback.