Every industry is full of charlatans and poor advice. Unfortunately, some cost you more than just lost money or lost time.

In this case, however, the participants may more likely be vulnerable. They are seeking some solution to their problems, and mindfulness is promoted as one. As the author makes the case, it really was a solution to his problems. But it seems he took it too far.

Isn't this a common/popular stereotype in so many movies? Hoity-toity protagonist believes they're more educated/better than the savages who follow old tradition, then have to eat some humble pie.

An age old tale we can't seem to learn.

There are equal number of these where after a short training montage the protagonist is not only an expert in said tradition, but in many cases better than the long term practitioners.

So maybe people are focusing on the second lesson rather than the first.