Telemetry can be privacy respecting. For example it may be useful to know the average page load time. The browser could record 100 different page loads and then send the median time.
It almost can not by definition, as every telemetry will include user IP address which is considered PII. Regardless what the stated purpose of that telemetry was, private information will leak and that browser can not be calling itself privacy respecting. Zero telemetry by default is the only way a browser respects user privacy.
If the user opts-in into telemetry then obviously it is user's choice, but usually browsers with telemetry do not make this an opt-in choice.
If the user opts-in into telemetry then obviously it is user's choice, but usually browsers with telemetry do not make this an opt-in choice.