I'm not sure I get your point.   I've got no problem doing business with someone who is visibly atheist,Christian, Jewish, Muslim, Hindi, Sikh, etc.  Do you? 

It doesn't matter if a politician is visibly religious.  The only thing that matters is how they treat others.  Respect is what matters.   Hiding one's belief system to achieve some secular ideal is a slippery slope.   All politicians should be themselves.  That includes race, sexual orientation, gender and religion.