Why is everyone so hung up on Mitt Romney's Mormon thing?

Mitt Romney has like the cleanest track record out of any of the presidential candidates, he turned around the 2002 Salt Lake Olympics from a $379 million deficit and make a profit, he is a successful entrepreneur, He has degrees from Harvard and Stanford, he fixed Machusetts's health care system, he's never had a divorce, he has a strong family, and he has good values. Why does the fact that he's mormon keep people from voting from him even if they know all of the other stuff? JFK was catholic, but did you see the pope taking over the country? Why should Romney be any different?