They are one of many, albeit facebook being on the more influential side, platforms through which misinformation is spread. And of course education is the main handle to push to stop spreading of misinformation. But facebook earned I don't know how much money on this and they tried to minimise the problem out of monetary concerns.
We thought the Internet would bring prosperity and an explosion of knowledge growth. And it surely did. But it also connected millions of less educated people who never knew that there were so many others out there - because they never read what they believed in the newspapers. And now they know that many others share their views. Again, education is at the core of a solution to this misinformation crisis. So maybe call the structural problems the burning embers and facebook the accelerant.