I don't think so at all. The author supported their claim with that indicate Sal Khan doesn't fully recognize the impact of PCK, and gives specific examples in Khan's lessons.
While PCK is a "buzzword", it does represent something very real in learning: That Instructors (be they amateur or professional) must understand the hidden challenges of the material they teach. Specifically, in ensuring that misconceptions do not propagate and embed themselves into a pupil's mind. In math, misconceptions can be particularly troublesome as the facets of mathematics, particularly at the elementary level, carefully layer on top of each other.
If you want an example of this that falls into the sphere of stuff closer to HNs, look to Zed Shaw's Learn Code the Hard Way series.
Shaw puts exercises and examples in front of readers designed explicitly to prevent the reader from developing weird misconceptions about the way a programming language (or programming in general) works. That's often why readers will say things finally "clicked" when they work through his material. Shaw may not be familiar with the buzzword term "PCK" but he definitely recognizes the challenges in teaching each concept he presents to the reader. You can see part of this come through with his critique of K&R C.
While PCK is a "buzzword", it does represent something very real in learning: That Instructors (be they amateur or professional) must understand the hidden challenges of the material they teach. Specifically, in ensuring that misconceptions do not propagate and embed themselves into a pupil's mind. In math, misconceptions can be particularly troublesome as the facets of mathematics, particularly at the elementary level, carefully layer on top of each other.
If you want an example of this that falls into the sphere of stuff closer to HNs, look to Zed Shaw's Learn Code the Hard Way series.
Shaw puts exercises and examples in front of readers designed explicitly to prevent the reader from developing weird misconceptions about the way a programming language (or programming in general) works. That's often why readers will say things finally "clicked" when they work through his material. Shaw may not be familiar with the buzzword term "PCK" but he definitely recognizes the challenges in teaching each concept he presents to the reader. You can see part of this come through with his critique of K&R C.