National Association of Evangelicals is the front group for left-wing liberals who want to say they are evangelical without all of the embarrassing “sin” stuff.
They were put together for the primary purpose that the MSM would have someone to run to for a pull quote opposing those crazy right-wing evangelicals..like myself.
He is, as noted, called upon by the MSM as an "evangelical" detractor amongst other evangelicals. This is how his name became somewhat well known.