Is the article about something else than how math on Khan Academy was thaught?

I remember minimal videos (3-13 min, usually 5-8), and then exercises drilling the techniques until you understand it and don't make mistakes. If you got a perfect score (no mistakes whatsoever), you went a little faster.

That's learning by doing, or am I wrong? Or are there no exercises for things other than math?

Yeah the article feels as though its describing Khan Academy from 10 or more years ago - it is quite odd.

"What he has never had is pedagogical knowledge: an understanding of how people learn, what motivates them, what makes the difference between someone who pushes through difficulty and someone who types “IDK.”"

It is almost as though the author thinks that Khan Academy is an organization of 1, and that they don't employ learning scientists and have a content team and don't publish research papers in the learning science field.

You are wrong in understanding the article.

Khan: Videos + rote exercises

Learning: Projects, complex problem-solving, exploration, argumentation, etc.

Dewey is worth reading.

Sounds like you should read the article if you have questions about what the article is about?