What makes you think all conservatives are Christian?
Actually, I would suspect that many are not christians but keep up appearances in order to get votes.
What you have to remember is that religion is the distraction for the Republicans. While Republicans try to stop any health care bill that would help the middle class and hurt insurance companies they have to convince the middle class that they are on their side. What do they use? God talk. So what happens? They get middle class christians to vote for candidates who are against the interests of the middle class.
Republicans are anti-union. How does a lack of unions help the middle class? Republicans are against socialized health care. How has private health care and insurance helped the middle class compared to other countries with socialized health care? Republicans are against social safety nets. How does a lack of social security, Medicare, and Medicaid help the middle class? How does deregulation of markets help the middle class (e.g. the recent housing market crash, credit card debt)? All of this is ignored by many voters when Republicans claim "God is on our side".