Common sense would normally tell a business person NOT to alienate a good part of his customer base by being discriminatory but apparently the gentleman you mention does not possess common sense. Not only will he anger the members of the particular religious group, he is also disturbing to the customers like yourself who are appalled by his behavior.

I don't know the legalities of the situation but I believe he will regret his actions when he sees the negative effect on his business as time goes on.