It's a good thing this "Watching a playthrough is just as valid as playing the game!" stuff didn't exist in the 2010s. Back then YouTubers had to argue that them playing through the game wasn't infringing on the games original market to prevent their footage from getting claimed.
Hey so uh.. YouTube decided to add the dumbest hidden feature alive and now attaches your username to shared video links! So hereโs how to disable it.