I disagree. It's good advice for people who deal with the occasional inflammatory comment. Or people who are having their first exposure to a large audience where negative comments are inevitable. For people who have actually been through long term bullying (I too have been through this), this advice is not helpful for the exact reasons vanderZwan stated. You can try to grow thick skin at first, but over time, even that thicker skin will be eroded and you will need a reprieve before you can recover.