Every single example on that page was clear bunk -- showing the worst habits of some developers, and making clear why they are terrible.

I think if you've gotten as far as that chapter, it would be pretty impossible not to realize it was tongue in cheek.

At the top of the page is a big warning triangle that says "Irony detected."

No other chapter includes such a prominent warning. I think it's pretty clear that the "gag" is specific to that chapter.