My comment was in reply to delinka's TL;DR. And you seem to be using a similar one. I don't know that it's "representative of the right way" to put criticisms like this in such a public forum, but it's not exactly new either. The first article is (is that the for-profit founder you're referring to?) definitely not constructive criticism. This article is in response to Khan's rebuttal, and at least offers a claim of more substantial research into Khan Academy's offerings before they provide their criticism.