I tell myself it's not liberal, it's post-evangelical
This review of Enn's Sin of Certainty had a great description of post-evangelicals (a term I'm hearing more and more) at the end, which addressed the isolation issue that @Keith_Furman alluded to. It is precisely because post-evangelicals aren't really theological liberals that they don't really have a place of their own in the current American church setup.
When I read the endorsements for Enn's latest book in a pre-release e-mail I got, I thought, "Hmm. Those are not my people anymore." I stopped reading Brian McLaren and Rob Bell and Tony Jones about a decade ago. I actually enjoy reading Enns more in books/articles where he interacts with or writes alongside other Bible scholars, like those Zondervan counterpoint books or the Books and Culture symposium on original sin.
Personally, I'm comfortable enough being a bit of an outlier in a mainstream Evangelical church. The "progressive" end of Christianity goes places I'm not happy to go theologically and I get annoyed with what seems to me to be a pendulum swing from an uncritical politically conservative orientation to an equally uncritical liberal political orientation. I'm evidently not as damaged as some people were by their Evangelical experiences and the constant moaning and outrage about how awful "fundamentalists" are from the progressive end is just as tiresome to me as the constant moaning and outrage about how awful the "wolves in sheeps' clothing" are from the conservative Evangelical end. Being judgmental and self-righteous is not attractive, not matter what politics or theology inspires it.