Attn: The reason people are not allowed to release the videos (At least my logical explanation) is that the channels will be investigated by YouTube. You are not supposed to post duplicate videos. The first person to post the video will be able to keep it, but anyone after that who posts it risks having their channel deleted or suspended.
This is to avoid having videos illegally copied without the creator's permission. Even if the creator does give permission, sometimes the system/people who review it don't notice it and/or don't recognize it as valid permission. This happened to some of my friends when they reposted one of my videos on their channel that I recorded with them - Their channel was deleted.