This may or may not be an obvious point, but--the appeal of Gregorian chant and polyphony is not about politics or ideology.
Alas, recent decades have seen a great deal of political/ideological division in the Church, both those related to specific questions of Catholic teaching and practice, as well as those arising from the broader society. And, right or wrong, certain things become identified with such factions.
Here's an example: the practice of concelebration.
At dinner the other night, chatting with a priest from up east, he referred to "concelebration being shoved down our throats"--meaning that those who might be termed "progressive" had done the shoving. That suprised me--I explained that in my diocese, at one time concelebration had been controversial and avoided, for precisely the opposite reason: that it offended some of the more "progressive" folks, apparently because of ordination reserved to men, and that those who were more traditionally-minded count it progress as more concelebration is allowed and practiced.
I.e., there are fault lines and some things end up accidentally on either side. It seems clear to me that sacred music, and even the entire aesthetic of liturgy, are such matters.
At this colloquium, I have spoken to cheerful, self-described "former hippies," who were definitely not Republicans; I just chatted with a gentleman from out west who, at the same time, disagrees with Humanae Vitae (Pope Paul VI's encyclical upholding Church teaching barring artificial means of regulating births), and is deeply devoted to the classic Roman rite, and the sacred music that pertains to it.
I don't know if any other conversations have broached political topics, but I suspect not much--because while many of us might naturally assume, or even hope, that our table companions share our views, on the other hand, we hope in a different way they don't.
Because this isn't about politics. Rather, it is about a treasure of inestimable value (what Vatican II called sacred music, if memory serves) that is our common inheritance.