Because now you got something worth $71k that you can resell. That Youtube video doesn't have any value or owner and nobody paid for that. The clip in itself is not important, it's the fact that it became a unique item somebody paid for.
You just encapsulated one of the dumbest shyts about capitalism in just a few sentences.
The constant effort to put a price on things that used to be free. How has that ever improved society?