The difference I see is that it breaks previous expectations. Ads in media have a long history, and there's a bargain that people understand (even if they don't fully understand the details).

Operating systems historically have not been like media. Perhaps this is the future (shudder), but pretending there has not been a difference doesn't get us anywhere. And it is jarring: compare it to one day, ads start appearing on your towels at home.

Personally, OS ads and invasive telemetry are way, way too invasive for me. Never used Windows as more than a utility thing for specific apps, but I'll never use Win 10 without crippling the mothership comms, and I'm moving away from OS X as well, because of the increasing cloud-everything centricity and the neglected unix subsystem.

Finally, this is probably a complaint specific to me and a not that many other people. I do systems engineering professionally. When OSes start doing things that I can't control and start communicating without explanations as to what, exactly, is going on for reasons that are not driven by my intent, I cannot trust the software. My machine, my environment, my rules.

People always jump to the phone comparison here. My phones are rather locked down too, snd I'm not happy about the direction, but can do little about that.