Where is your information for such an assertion?
The information is all around us. How often is Pat Robertson condemned for making extreme statements? Sure, it happens a little bit. Mostly he shoots his mouth off and no one cares.
But he's still on TV. ABC still runs his program. Millions of Christian moderates in America, and they let this guy speak for him? Remember that Christians have pulled hundreds of TV shows off the air when they felt they threatened their faith. Pat Robertson's somehow unstoppable?
The right wing in America, prior to the mid 1990's did not receive much spotlite and more moderate views of Christianity kept it from being overwhelming in politics.
Nonsense. The public voices of Christianity in this country have always been extremist ideologues. William Jennings Bryan. Cotton Mather. Gerald Winrod. Johnathan Edwards. Ralph Reed.
They were squeeky and they got the grease.
And moderates refuse to squeak. Look, I don't disagree with you that the attention goes to the extremists. But that's not because the media favors extremists; it's because religious moderates refuse to offer any competing voice, for fear of creating a schism within their own religion, or for fear of appearing to side with outside forces against their own religious peers.