The political left has really decided to go nuclear over Flock, but I'm not understanding the fundamental principle from which this view arises. Libertarian sorts don't like it either -- but that's entirely consistent with their entire existence. Is this a broad-based phenomenon on the left, or are sections perfectly fine with it? Some of the other comments here seem to endorse full on 1984-style surveillance, so perhaps this is just a libertarian-left-leaning Silicon Valley strain of leftism that's in revolt against Flock? While possible I don't traditionally see outfits like New Yorker falling in that category. When the worldview is very permissive of broad state power and often admiring of Europe, which has itself been struggling to fight off legislation weakening encryption, it's hard to make sense of this.
I'd be curious to see if Mamdani or someone similar employing Flock or an equivalent would yield the same firestorm; if not, then it's not a principled stand against surveillance, rather just another form of political warfare. Perhaps Antifa wants to not be tracked in certain locales, is less concerned in other politically favorable locales because they know they won't be prosecuted anyway?