Deconstruction of anonymity is an academic and agencies proven success.

It can be called anonymous when it goes through TOR to be sent, etc… which is not even considered afaik.

If you rely on the receiving party to not store your IP and other sent details, then it’s not anonymous. Sadly, some companies get evil, get compromised or get internal threats…

And yeah, opt-in is minimum or the software is called a spyware. And yes, with this definition recent Windows is a spyware.

If you want an argument about privacy, watch the insightful talk by Halvar Flake on security vs. death squads… chilling but sadly true.