It wasn't so much Oprah that was of interest. Rather as Kidd comments, an understanding of phenomena of Oprah helps us see the 'moralistic therapeutic deism' that much of modern Christianity has been reduced to. In other words, the 'faith in a God who wishes for good people to be successful, happy, and materially blessed, and then to go to heaven when they die' spirituality that Christians so often are cooped into'.
In this system, Jesus is unnecessary notes Kidd. Or as I'm more inclined to observe it's not that Jesus is absent for Christians, its just that He trumps Oprah, or Dr Phil for this way of life.