Yeah, obviously giving every voice equal weight isn't practical, and whatever filter you apply is likely to introduce some kind of bias. I'm not saying that the fact that you get echo chamber effects devastates the whole notion, just that it is a failure mode you should be aware of if pursuing something like this, and that "local in values and principles" is worse than "local geographically" as pertains to this specific effect.

Edited to add:

In fact, "mostly local" helps address a failure mode we see presently - if you only hear news from your tribe and a little from neighboring tribes, things you hear about are far more likely to be significant.