Since we’re at it, I propose that any post denigrating e.g. the music of
Pierre Boulez, or praising, let’s say, the music of
Chopin, be considered trolling, and be deleted automatically and immediately, with no prior notice and no questions asked.

I’m not a member of that other classical music forum so often mentioned here, but from what I’ve read (and has sometime been commented here), even if there’s apparently no politics there, music discussions often degenerate into the unpleasant and the ad hominem, and I understand members interested in some areas of the repertoire have been forced out (so to speak).
The decline of new memberships here on GMG cannot be attributed AFAIK to the political thread. Let’s face it, the golden age of Internet forums ended several years ago (at least from what I see in other forums here in Spain). On GMG, though, we have steady and healthy traffic of mostly very pleasant, entertaining and sometimes very informative views on music (and sometimes, from members who figure prominently in the politics thread). Let’s not change that.