He's operating from a flawed premise. He writes "The general consensus among B&W photographers always seemed to be that you can overexpose color negative film, but shouldn’t try that with B&W film or you would risk losing your highlights. The mantra “expose for the shadows, develop for the highlights” reflects exactly that, and suggests to overexpose and underdevelop."
I've never seen anything that suggested that overexposure of traditional B&W film would risk the highlights; on the contrary, the latitude of such films is generally even higher than the most tolerant color negative films, like the Portra he used for his color example. The basis of the zone system is the roughly 10-stop latitude of photo paper, not the negative, which has far more (15+ for most modern emulsions).
The zone system is intended to produce the greatest tonal range in the most important part of the scene being photographed. If all one wants is a usable negative, then the zone system is a waste of time; I certainly don't use it in street photography. Hybrid processing and printing make it less of a factor in the final result (the print). But it's still very useful in things like landscape photography, especially with medium and large format shots intended for big prints, for extracting the maximum information in the crucial portions of the scene.
What I do not like is the self-aggrandizing arrogance of his title and presentation, acting like he's pulled back the curtain on some sort of huge scam to reveal The Truth to the world of photography. There may be something worthwhile in the post (i.e., just err on the side of overexposure and you'll be fine), but that could have been said quite differently and still made the point.