This is what you said, among others:

> Every operating system now phones home and uploads copious event logs.

There is nothing about telegram in there.

Linux distros are much better but they can still phone home. Here's one example: https://help.ubuntu.com/community/UbuntuPopularityContest

For awhile Canonical had a deal with Amazon that was highly questionable. https://www.gnu.org/philosophy/ubuntu-spyware.en.html

The most dangerous however is the auto-updates. Even if the software is safe today, how do you know what tomorrow's auto-update will bring?