Faith has long been a convenient thing to hide behind when justifying discrimination. Slaveholders used it. Segregationists used it. Interracial marriage opponents use it. Now folks who oppose gay marriage use it. 

If you don't want to serve the public because your religious beliefs make you feel ickie doing so, don't open a bisiness. Instead, open a church or private club. You can have secret, pro straight handshakes and everything and nobody will care.