Sounds really strange and weird to me...never have encountered something like this, and I've been around a while!...I know that are some people that are "overly religious" and zealous about their Church. And some business do have religious signs all over their walls. I take it with a grain of salt when asked if I attend Church, etc., and make my answers "short".
But to refuse "service" to someone because they don't attend Church? Strange to me!
At one time, a co-worker, who was overly religious keep "hounding" me about Church, and I became frustrated, and told my boss about it. My boss "gave me a lesson" in humanity, and said...."He's just overly religious. He means no harm! Just say "Thank You" and walk away....which I did afterwards, and the guy got the message, without me having to curse him out!
Some of my old time friends are deeply into religion now, also, and before they never were. But I did not cut my friendship with them. I accepted it. But kept my own ideals to myself.
But to walk into a Hair Salon, and have them tell me they would not cut my hair unless "I went to a Church, or to their Church".....something's not right there! I would have just said, "OH, well, thank you". And walk out! and never go there again....Let them "cut their own throats" because their business will suffer.