The linked-to "Part 1" includes the "myth" that his discussion is referring to, and so is much less misleading. However, personally, I'm not aware of anyone interested in this kind of thing who holds those myths to be true; it's very common knowledge that if you ingest any calories, or taste something sweet, etc, it will trigger the release of insulin. (However, I'm confident that you and the Part 1 author know your target audience, and these myths perhaps make perfect sense to address to them).

Likewise for his comments on glucagon, it does not "cancel" the effects of insulin, it rather has the opposite effect at the same time. Also, in a natural system (i.e. without intervention), secretion of insulin typically suppresses secretion of glucagon, with some rare exceptions. He's stating a supposed myth and then taking it down with another one.

The two papers cited for his interpretation of the role of glucagon are quite old, from 2001. There have been dozens of studies since then, confirming the role of glucagon in lipid metabolism, from many different perspectives.

Here is one published last year

https://pubmed.ncbi.nlm.nih.gov/31068828/

"Collectively, emerging data support an essential role of glucagon for lipid metabolism."

There are dozens of others -- you can get a start on this reading by seeing who has cited the two papers he referred to.

I didn't understand that the main point was "debunking the idea that insulin is what makes us fat", since I don't know anyone who believes that. Chronic poor nutrition can make you fat, sure, and rising basal insulin levels tend to occur as a result of that, but saying "insulin is what makes us fat" sounds a lot like "yellow fingertips cause lung cancer". Nobody I know believes that is true. I have to keep up on these things for my work, in drug development.

Regarding "being 2 steps removed", yes, it seems like some "broken telephone" is going on.

Be well!