One hacky (but simple) method would be to put this at the end of qa-include/pages/user-profile.php just before return $qa_content
unset($qa_content['form_activity']['fields']['points']);
The better method would be to override the form_fields method in your qa-theme.php. I think this should do it:
public function form_fields($form, $columns)
{
unset($form['fields']['points']);
parent::form_fields($form, $columns);
}
Hope that helps.