Telemetry (if it’s truly telemetry) is nowhere close to “tracking”. People conflate the two all the time. One can provide useful, anonymous metrics (e.g. “user enabled feature X”) without doing anything but incrementing the counter for “feature X”.

The “Firefox Problem” is that all the power users disable telemetry, so all the “cool” features that power users like (but never get used by “regular people”) get ignored or removed instead of improved because, according to the metrics, “nobody uses them”.

The user doesn't conflate the two, the developers do, and that's why we turn off telemetry, because its damn close to tracking.

Knowing what (vulnerable) version of software a user is using transmitted in the clear was absolutely a part of the NSA monitoring error information from windows crash logs https://www.schneier.com/blog/archives/2017/08/nsa_collects_... - so forgive me if I do not trust the developer to know what makes me unsafe or not.

If you enable telemetry by default I will do my best to never use your product.