Now we know why. Facebook rewarded Trump’s salacious, dishonest click-bait campaign by charging him less than his opponent.
1) Trump’s Team discovered it is cheaper to spread propaganda than truth on FB and ran with it
2) Facebook charged one campaign a fraction of what it charged the other
...and the campaign that got the discount was the one using propaganda to draw clicks.
They weren’t optimizing their “message”. They were gaming Facebook’s auction system - with the active help of Facebook itself.
Facebook staffers actually worked onsite with them.
Facebook won. America lost.
Now it’s Facebook’s turn to lose.