But not every telemetry is bad by default. Like in Windows 10 where some telemetry is needed or Microsoft can't fix random user configuration setups.Microsoft. Google. Amazon. Apple all use telemetry for diagnostics and subtle in-OS ads to sell their products. Open-source does not give it the legal status.
Also OpenSource doesn't mean it's telemetry-free nor better. OpenSouce mostly switch the owner (fork) or just dies and get problem with man power/ maintaining the code and keep it up2date & secure and of course that's harder without telemetry - if possible at all