Get earning from YouTube is not a passive income because you have to make a video creative to be able to make people interested in watching your videos and it needs to be done on a regular basis with new ideas every time you want to make a video so obviously isn't passive income.
To my point of view I don't agree that youtube is passive income in the sense that "passive" means do nothing but you always have a source of income. Assuming that someone is doing his first video and many people subscribe it and at first earns some money of it. Do you believe that next years of his life he continues to earn money? Of course not; because his subscribers will already have seen that video and if he is not talented to keep them, that is to make a new and better than previous one, they will leave, unsubscribe and views per day will go to zero that is zero earnings.