Since I am at work, I only watched a little bit of the first linked vid. That small rocky bumpy terrain would not require the shock rebound set all the way out , nor a rebuild.
The people that need the rebound set at max and/or rear shock rebuilds, are the guys that ride in a such a way, that the rear shock gets fully compressed, either with small jumps and/or whoops. When the stock shock gets fully compressed, the rebound damping needs to be increased...dramatically.
Edit: The guys that have their bikes bouncing them in different directions from the way that they are trying to get the bike to go, know if they need the rear shock redone or not. I would not advise anyone who does not know what pogo'ing is, or if their bike is doing it, to have the shock rebuilt.