I suspect more moderate leaders like Warren have a lot to do with it. Warren’s own views on evolution, while less hysterically expressed than those of [Albert] Mohler and [Ken] Ham, are not finally distinguishable from them. In a 2007 Newsweek debate with Sam Harris, Warren declared, “Do I believe in evolution[?] The answer is no, I don’t. I believe that God, at a moment, created man... Did God come down and blow in man’s nose? If you believe in God, you don't have a problem accepting miracles. So if God wants to do it that way, it's fine with me.”
In his opinion on evolution, Warren displays his own considerable scientific illiteracy. That in itself is not too big a deal; one man rejecting evolution is not news. But when that man is Rick Warren, a major Christian figure who has, despite his conservative credentials, pushed the evangelical envelope on a number of environmental and social issues, the rejection carries a lot of freight.