You make a good point, one that I pointed out in a steemit post. Again today on DTube I found a video that is a direct copy of a YT video from 2010. The problem isn't only that isn't original work, but that the copyright owner could come after the uploader for copyright infringement. In this case the copyright owner is a foundation with Headquarters in New York and India and the chances are slim to none that the DTube uploader could win a case against an organization that is represented in 40 Countries. If you don't know what you are doing, only upload things you created yourself. I personally publish under my real name and have written permission for most of my videos where copyright issues could arise. Hope this helps. Greetings!