Sure, if you want to take a purist stance, we should start by inventing a universe free of third parties, to borrow from Feynman.
Meanwhile, the goal of most of these private groups isn't to stick it to the man, or make sure all data is eternally private, but just to talk to each other in a non-public setting. It's OK to use a tool for that you haven't entirely built from scratch.
Most humans, your "the people" (really? in quotes? did you want to write sheeple?), care more about getting on with their life than absolutist stances. They notice just fine, and they adjust as much as they feel the need to adjust.
Meanwhile, the goal of most of these private groups isn't to stick it to the man, or make sure all data is eternally private, but just to talk to each other in a non-public setting. It's OK to use a tool for that you haven't entirely built from scratch.
Most humans, your "the people" (really? in quotes? did you want to write sheeple?), care more about getting on with their life than absolutist stances. They notice just fine, and they adjust as much as they feel the need to adjust.