It's sending back arbitrary data to someone else without explicit authorization. This data can contain anything including information about the running environment, the contents of files on the computer, other running programs.
It doesn't matter that it's Microsoft instead of an Estonian teenager doing it. You own your computer. You explicitly decide what data comes from it. NO EXCEPTIONS.
You are giving very explicit authorization by agreeing to the EULA.
> You own your computer. You explicitly decide what data comes from it. NO EXCEPTIONS.
That's still true. And by installing a product and agreeing to a EULA which includes a section on telemetry you are doing just that. Thus, your options are "don't install the software" or "opt-out".
It's also unlawful under the GDPR.
It doesn't appear to say clickwraps are non-binding, only that it has to be "conspicuous" and basically that a user knew they were agreeing to something. Unfortunately that too is open to interpretation. As with most things of this nature, if someone wants to sue, they can sue, and it's a resource fight in the courts.
[0] https://en.wikipedia.org/wiki/Specht_v._Netscape_Communicati....
GDPR does not make collecting aggregate data unlawful, so unless you can prove that the data collection is identifiable then GDPR doesn't apply.
Bullcrap. Many people's Win7 installs were upgraded to Win10 without their consent.
To claim otherwise is blatantly dishonest.