Brock, Parker, and Crossan are all semi-Pelagians or worse. Brock comes from the Campbellite tradition (which denies original sin altogether); Parker comes from the Wesleyan-Arminian tradition (which claims that the depravity inherent in original sin is neutralized by universal prevenient grace); and Crossan comes from the Romanist position which assumes that, whatever original sin is, it is easily washed away by holy water.
A little Reformed theology would be helpful to the author of the article, I think.