I'm very surprised by the discourse in this thread. I understand that people were given lots of warning, but that doesn't excuse that they just had their purchase recinded. Why not just allow download of an old version of Minecraft Java still?
I'd consider myself a Microsoft fanboy as I've had Xbox live for nearly 2 decades and Game Pass since it came into existence. Removing people's purchases for any reason is a scummy move.
Devil's advocate: the login requires a server, so even old versions won't work unless they keep them online. And without support, they will be easy target for hackers.
I hate this, and honestly the best would have been to not change the logging at all. I bought a game that didn't need a MS account to play and this change doesn't bring any benefit.
If you self host an older version, you can allow non-authenticated users. I did that for years so my kids could play on our LAN with just the one license. I eventually bought a second license, but we still haven't played outside our LAN.