Of course Khan lectures are not all encompassing just like his lecture on IPOs aren't but they provide a great deal of entry level knowledge. If the author ever imagined that WW2 could be explained in one short Khan Academy video his expectations were wrong not Khan Academy itself. Personally, I believe he is a spiteful fool afraid of a revolution in education.
Please refrain from name-calling.
On one hand, you're rightly pointing out that one fifteen-minute video by one guy can never be an all-encompassing summary of thirty years of world history. And you're right.
But then you're talking about the Khan Academy as being some kind of "revolution" in education, even though the Khan academy still consists of fifteen-minute videos by one guy. This is the article's point -- there's some pretty serious limits to what we can expect out of a Khan-Academy sort of model. He's done a great job with introductory mathematics, but there's a crapload of work that would need to be done to make it an adequate source for other subjects.