What does this say about America as compared to the UK?

Tony Blair kept his conversion to catholicism to himself until out of office because he did not want the British people to believe he was a "religious nutter." So why is it almost a requirement in this country to be a "religious nutter?" I have also read a book penned by Pistols front man Johnny Rotten (John Lydon). When he came to the US, he was shocked that abortion clinics had protesters lurking outside. Why is America so backwards about religion?