[6bmike]

It is very common to use the term 'vector' when plotting points, which is what Mr. Kelley was doing. Nowhere in the book does he claim that Inertia anything different than how it works under Newton's three laws. That would be a mistake in science- not plotting points in a legend about Horizontal Hinging.

So, is this something you discovered - or read from others still trying to rip HK's use of basic science?

Weak. At least start off with a blockbuster.