Yes they are real because the God sinabi in the bible that the ones who's time continue bad will see evil spirits(demons),but the good could see mga kerubin or other good spirits. Now not all people can see spirits. I saw one in my room,but the creature was red with a tail. He smiled at me. Some demons come out sightly just as a sign to attack people. They can also touch you. Otherwise, watching it in the tape could be real but not all.
Everyone has their own beleifs, whether they are religious or not. Me? I don't believe in demons a book or movie or a tv ipakita can't tell me too either. I have seen lots of pelikula and tv shows that ipakita demons like zombies but they are mostly fake. And most bidyo that are shown like what you are discribing are usually fake. It's like people saying they believe in ghosts, well, I've never seen a ghost but I'm not ruleing out the idea of ghosts though. Anyways, basically, everyone will either believe in them or not. Like Demons, they may be real, they may not, but I'm not saying I believe in them, cause I actually don't. If that makes any sense.
It counts sa pamamagitan ng your religion. If you believe in them, you see them. It also counts on how you act. If you act rude. You see demons and Ghosts. If your a true believer you see mga kerubin and friendly ghosts. The YouTube bidyo are sometimes fake, you can also hear them too. Sometimes you can't see them, they're everywhere you go . Some people don't get to see them. So, it's part on how you act and what you do. Also, you have to respect your family members and people. If you don't, you won't live longer. Back then. They would throw stones at CHILDREN who have been pagganap bad so they won't grow up doing it. And yes. Demons are real
Honestly, no one will really know. Some believe, some dont. You can make them real if you believe in them, you can make them fake if you dont. Its all on how you see it in my perspective. People that do believe in them might take walang tiyak na layunin things for them while people that dont may take things they do as something else.