Welcome to the forum, may all your questions be answered here!
Yes, some of the videos were created by 3d party vendors. They may have originally published them in the wiki, but then for whatever reason access has been restricted to them.
I was able to view that video by going to YouTube and searching on the video title; it came up among the search results. But I noticed that the EMR being used in the videos is a proprietary fork of the Community Edition OpenEMR. That may have be why the links are inactive; only videos of the CE should be posted in the OpenEMR wiki docs.
And be wary of proprietary forks: they usually function differently from OpenEMR CE and some have associated costs that CE does not.