Do you have a source for that? Not challenging it per se, and not putting it beyond Microsoft. But I have a Github account I created over Tor, with an anonymous onionmail.info email address created and accessed only ever over Tor, and I can file issues and post comments to the Qubes issue tracker that others can read and respond to.
So according to the information I have, what you say resembles FUD, which is no good as it discourages contribution to Qubes. What you say might in fact be true for new accounts in 2026, but I’d like to see it verified.