While I appreciate Rob Bell’s creativity, and would not want to judge his motives (I’ve not met him, nor read enough of his writing), I don’t find his logic, exegesis or theology very sound.
So, what is an Evangelical?
Here is a good definition which highlights the central driving features of evangelicalism.
To define “evangelical” we need to pay attention to those who have made it their life study to come to terms with this movement, and two scholars have done just that: Mark Noll in the USA and David Bebbington (The Dominance of Evangelicalism: The Age of Spurgeon And Moody (History of Evangelicalism) ) in the UK. They agree on this: an evangelical is a Christian Protestant for whom the central ideas are the leading authority of Scripture, the necessity of personal conversion, the centrality of the death of Christ on the cross as a substitutionary atonement, and the importance of a life of active following Jesus, seen in such things as Bible reading, prayer, church attendance, and deeds of compassion and justice. That is the standard definition of evangelical. This definition summarizes those who care about getting this term accurate. It is not a definition designed to exclude some of whom they are worried. It’s big tent definition, but it bears no ill-will toward others.
Now my observation today: I’m seeing a baffling desire by many who almost never talk about any of the above four ideas (as central to what they believe) but for some reason want to be called “evangelical.” They make a point to say they are evangelical. To be committed to justice or compassion as the central pursuit in life does not make one an evangelical, though evangelicals should be committed to justice and to compassion — and shame on those who aren’t. But what makes an evangelical is a commitment to the above four ideas (Bible, conversion, cross, discipleship).