Firstly, publishers need to rethink the entire ad model of the internet, and shift it to a 1st party data model rather than the 3rd party model that exists today.
Secondly, publishers need to change the way they report these stories, because, today, your Facebook-centric focus is out of tune with the real problem.
Thirdly, the tech industry needs to change.
Imagine if Facebook were to disappear tomorrow, would that solve this problem? No, because then the politicians would just use some other data and find some other tools ... and keep on telling different voters different things. The only way to actually solve this is to regulate the politicians. The politicians are the ones who shouldn't be allowed to do this.