The way Mozilla does telemetry is different from how most places do.
I think that the biggest issue with these discussions is that there always seems to be this assumption that there is only one way to do telemetry, it always contains super invasive PII, Mozilla's telemetry must do the same, and therefore Mozilla's telemetry is just as evil as anybody else's.
Mozilla is remarkably open about how its telemetry works, beyond just being open source. Maybe this is more a problem of that information not being surfaced well, I dunno. I get that some people are philosophically opposed to telemetry no matter what, but I have seen enough cases of, "Wow, I didn't know it worked that way, and I'm actually okay with this," to know that informed users are not universally opposed to it.