Don't worry, FF will do an automatic update to re-enable it. Again. Without your consent.

They will turn it back on for you. I could swear I've had it turned off a few times already before, and I'm definitely sure I did it at least once yet here we are :).

Telemetry in itself isn't the end of the world, but disregarding the settings your users chose is such a weird behavior coming from an organization that pretends to care about choice.