I Believe She's Talking About Professional Behavior

It's hard to believe that people need to be told the kinds of things agent Jennifer Laughran says in her blog post The Fine Art of Zipping It, or XYZ PDQ. Other professionals have to be aware of their public behavior all the time, why should writers, and specifically children's writers, expect to be any different? It could be because on, say, Facebook you "friend" people. Thus there is the illusion that you know your friends and can relax with your friends. But many writers go onto Facebook for the sole purpose of promotion/marketing. They are advised by promotion/marketing books/sites/experts to do so. They collect as "Friends," many of whom they don't actually know. The idea is to post info about their work in front of all these people, hoping that they will buy books or at least talk about you to others. So you go to all that work, and then do nonprofessional posts that will make you look, well, nonprofessional? I am mystified. Mystified, but also hoping I never slip up and do it myself.