Just an idea, but the videos may have gone private because
Sepp Holzer hosts seminars, and those have to be paid for. So it would, I think, be rather embarrassing to get caught sharing paid content. I do not know whether the video poster had permission for filming or not. I'm just speculating, and also, we did not pay to see his seminars, so sadly, we wouldn't get access anyways.
It does make me a little sad, because knowledge is power, and knowledge is just cool! (reason why I'm partial to open-sourcing), but we know the rules/laws. *sigh* Yeah, just a little sad some knowledge escaped our grasps...