How is it not anybody's content? Did Facts just fall out of the sky? Some human was responsible for testing a theory and creating said fact and publishing it. Even if you can't find the original source you could still reference is based on a journal or publication you found it on.

Well you not knowing something isn't a cause for no repercussions, if you didn't know to put your hand in a meat grinder is going to shred it to pieces are you going to be upset at the manufacturer for not telling you? This is the decentralised web, it's up to the individual to educate themselves, there's no hand-holding here.