These people had years to migrate their accounts, were told to migrate their accounts, and warned to migrate their accounts because the old mojang auth system is insecure and needs to be sunsetted, and when it does, they will lose access.
They sat there and played the "no, I won't move" game, and now they're upset because the thing they were told for years would happen happened.
And they would have had to have no social interaction with any minecraft player on any online platform and in real life in all those years, as well as ignore every email from mojang, never look at the minecraft website, and so on, to not be notified.