You can actually edit that config file and replace the email address with the one you want to log in with.
File should be in:
Well that’s how it works apparently.
However, good news, I figured out a new way of disabling/resetting the weird auto-login.
In the same cfg file, delete the value under
Cookie (more specifically the long ass random characters between the
[value][/value] tags). Save. Fire up the launcher. Be amazed. You’re welcome.