If you read the above link you can skip the first two self-congratulatory time-wasting paragraphs.
It's only by paragraph three that the proposal that silence as political speech gets taken up as the theme of the essay. For those who understand Cage's landmark work to indicate not actual silence but that whatever transpires during the allotted times IS the music (and this could be anyone who read Cage talk about visiting the anechoic chamber) this whole premise Andy Costello runs with is performance art and not necessarily a riff on Cage's published work or any iteration of its performance.
Now, in 2016, I taught a general music class to middle school kids at a private school in Chicago. In one class, I thought it important that they watch a performance of 4’33”. It failed miserably—the kids laughed at the performer and found nothing of value in the work. I explained to them that they were criticizing the piece before truly hearing it, so I offered them the challenge of performing 4’33” together as a group before they offer any critical feedback, and they unanimously agreed to the challenge. So, I told them we would officially begin the performance of 4’33” when I give them the cue. I set the timer for 33 seconds (the duration of the first movement), started the timer, and gave the cue to begin. Several of the students laughed and made silly noises within the first ten of those seconds, but I let the movement go on without reprimand. ...
Because whatever sounds during the allotted movements IS the music there wasn't any basis for a reprimand. Instructing the player to not play doesn't mean that the rest of the ambient sounds stop being what the music is.
Costello's would-be epiphany isn't necessarily an epiphany based on understanding what 4'33" does and doesn't do. had the opportunity to teach a music class at a private school in Chicago. Rather than construe this or present this in terms of privilege, it is, almost inevitably, presented as a musing upon silence and political speech and subversion. Just last week we were perusing here at Wenatchee The Hatchet comments from Cornelius Cardew and John Tilbury about what they considered the moral and intellectual dishonesty of Cage's enterprise as seen from Marxist terms in the book Stockhausen Serves Imperialism.
So when Costello writes "We need a pedagogy that uproots cowardice, questions authority, and subverts the angry, oppressive, harmful acts of the privileged classes in the oligarchical role they/we currently enjoy." with a footnote that says "I say “they/we” to described the privileged class because I feel that I belong to this class at times, and at other times, I do not." the surprise is that he only sometimes feels that he belongs to the privileged class." If there is a besetting systemic problem with people in academic settings in the United States, not seeing themselves as members of a privileged class having he oligarchical role of educator would be one of them. By means of a number of ideological flourishes teachers can convince themselves they aren't the establishment itself, but that doesn't stop them from being the establishment. Jacques Ellul described state education as a crucial form of pre-propaganda, not necessarily explicit propaganda in and of itself but a necessary precursor for the propaganda of more official sorts to work.
What 4'33" teaches us in this case is that it has gained enough prestige as a cultural artifact that it can be appropriated by a teacher as an occasion for an epiphany that may or may not have anything to do with Cage's work or its reception history but that provides a moment of self-comfort. Art can provide solace, to be sure, but considering how sweeping the condemnation of Cage was from Cardew and Tilbury forty-some years ago the lesson today is that if an art artifact has enough prestige and social history attached to it people left and right (politically and in other figurative ways) can find ways to rehabilitate it and assimilate it into whatever their views are in the here and now.