This guy should probably come out and say Khan Academy is eating his lunch and he is pissed about it. The passive aggressive approach to talking about companies with better lessons and teaching styles gets completely undermined when you realize that this guy is selling math lessons and you conclude that he thinks his stuff is better than Khan's. Yeah, maybe it is, but it looks really pretty weak to write an article like that and not mention the fact that you are selling a competing product. Where's the Chutzpah? Just say "Khan sucks, we are better, here's why".
Of course, the context is missing here in the writing, and Hacker News probably wasn't the intended audience, so maybe it was assumed people would make the assumption that Mathalicous' stuff was the better solution the author was talking about. But so far, the overall response has been pretty poor.