Yes, it is designed to handle manually because it’s in backend of this component.
In the order to do this, please look at this user guide http://www.joomlaboy.com/blog/27-civicrm-error-send-valid-username-password for your reference.
In addition, i think this function should have been added an option to handle automatically. I have added this to development backlog for coming releases.
Thanks for your idea and it would be best if you guys can raise your own ideas up there and we can hear you guys closer and try our best to reach the expectations of the majority of users.