So, where would you draw the line for allowing people back?
People getting off on inciting others to kill themselves?
Homophobic's bullying LGBT?
A person who has admitted to raping someone else?
A individual openly selling SN?
Someone who accuses others of criminal acts because they just don't like what they did?
The Mods / Admin have rules. When you sign up, you sign up to the rules. It would be an absolute nightmare trying to let some back and not others. It doesn't matter who the person is, once the threshold for banning has been met, it's been met.