I think it has nothing to do with the administrator or forum . It's the responsibility of the account owner to ensure the security of the account. I think it's probably because you didn't keep your account password properly. It's not because of security vulnerabilities in forum. Otherwise, hackers should steal a legendary account more profitable than a Sr account.
Honestly, I would say that my account wasn't secure, and it's not like I am blaming it on the administrators. My point is, why don't they at least allow user to confirm that they are changing the email; you need to understand that change an email is unlike changing the password; changing an email is more like changing account ownership so you cannot do that without confirmations. if we had the option to let us confirm change that we are making changes through email, none of the users would have been experiencing this, but instead, they get an email informing them that the email has been changed, by who? remains unknown.