As bad as it is, we have to count that this type of narcissist thinking is normal at that age (mid twenties), its a developmentally appropriate trait.
I'd have to disagree there. Historically, 20-somethings have exhibited far more maturity, education and leadership ability than they do today. Sociology professor, Robert A. Nisbett discussed this as a historical problem in light of a modern day youth dominated pop culture. For one example, he wrote: "The age of some of the most distinguished members in the long history of Parliament in England is a case in point, and we may suppose that the brilliant young Pitt would find it far more difficult today to lead the House of Representatives in supposedly youth-dominated America than he did Parliament in eighteenth-century England."
We may have a youth dominated culture now, but the end result is a degradation of the abilities and maturity of young men and women - a maturity that used to exist but is now being put off until later and later. This isn't to say that there aren't exceptions, but I don't see how anyone could deny that it's a problem.
What we should be asking is how the 40 year olds got this way, and why it's happening to the society as a whole, not just Christianity.
Both are important questions that are, for the most part, simply ignored. The Christianity question is still important, however. The church is supposed to be an example that contrasts with the problems of any society. That the church has not resisted this, but instead catered and even appealed to it, is a profound theological problem of it's own that is going to have to be addressed within the church.
Scott McKnight has mixed feelings about this book ... For obvious reasons, I really dig this part: "the juvenilization of the church is about immaturity, which is the same problem the writer of Hebrews faced, Martin Luther faced, Jonathan Edwards faced, and … well … almost all have faced this. Bonhoeffer complained about this as well." Exactly.)
Well, no, it's not "exactly the same problem." Luther faced a society where education, including obviously theological education, was denied to the majority of people. The educated classes in Luther's day knew exactly what they were doing when they were exploiting the superstitions and weaknesses of everyone else. Edwards faced the first mounting secularism in the colonies and Bonhoeffer faced a broken society of people who were bitter and dissatisfied with their mistreatment after the Great War. All of them faced the problem of sin, but every age has it's unique problems.
Our age has a powerful pop culture that dominates the time and activity of people to an extent that is historically unheard of. 20-somethings of our time have a whole wealth of educational riches at their digital fingertips (that is also unheard of in any other period of history) and ... most of them simply refuse to avail themselves of it.