(Source) Read the comments to get more background, much of which reflects my sentiments. (I know saying “my thoughts are in the comments” is rarely a good place to start anything, but in this case, it’s valid and relevant.)
It’s widely known that conductors, as well as classical music pedagogues in general, have their fair share of stern-if-not-cruel taskmasters. I have experienced teachers lecture, berate, yell, throw fits, curse students out, and in one particularly salient case, had a conductor close the key lid of a piano while I was playing through a fake book with a friend, before rehearsal. (“We don’t play that kind of music here.”) It’s never been a shining example of egalitarian learning, and most players, if not virtually all players, know this.
Overall, laying this at the feet of El Sistema is highly suspect. If you’re going to criticize these sorts of practices, criticize the nature of the system itself — but doing that would require examining not only the sometimes-if-not-frequently strict practices in this regard overall, but the economic and authoritarian nature of classical music in general. Not to mention the professional station (and possible book-promoting motivations) of the author himself, which carries with it its own forms of at least potential ironies.
I also wonder about the politics involved here, but the author’s comments are framed so heavily around playing whack-a-mole with a scattering of sources in near-ad-hominem fashion, I can’t really get a read on it, past a possible subtext. The author appears to be a scholar around musics in Cuba, and the sociocultural aspects therein, for what it’s worth.