Right, the danger here isn't stable unique data itself--there's already plenty of that--but the OS "telemetry" which steals [0] it and reports to Big-Brother along with too much other betraying information. Every site you visit, every program you run, the serial numbers of all your hardware, etc. Even if the GDID were totally absent, it would still be a correlate-able privacy nightmare.

Ultimately there's no informed consent here: The average consumer is disbelieving and surprised if you tell them what kinds of stuff Microsoft has/can put into a dossier. Nobody thinks: "Ah, Edge on a fresh Windows install, I'm glad Microsoft knows every site I visit, and can tell I'm a friend with someone because we use the same bluetooth speaker."

[0] It seems wrong to use the verb "leaks" when it's so obviously intentional.