That's the way, using strong passwords and changing the password with or without any hack periodically...
Why bitcointalk don't use a 2FA? It would be nice for security
Because it is forum based on old software in times when no one even heard about 2FA?
And new forum software which will probably use 2FA functionality is in development for couple years already.
So there is very little reason to waste time and effort to update current version of Forum with new features.