You certainly missed the point that after registering an account, you need to carefully store your data so that there are no incidents, like the one that happened recently, when a person simply forgot their password.
Also, do not trust letters received in PM. Do not follow the links in messages, since sometimes you can get a phishing link. There were cases when, after following the links, people thought that they accidentally logged out, but they remained on the forum, and they were asked to enter their login and password again. Every time you encounter such a situation, be careful not to fall into the clutches of hackers.
Likewise, do not save your passwords in the browser, since all your cookies can be decrypted, and others can get the password for the forum.
I had cases when there was a need for quick registration on some resources and confirmation. I used temporary mail. So in the history of these emails provided by services, there were many interesting things, including logins and passwords of other people. I think the case that the OP was referring to was identical.