Facebook and other similar systems reward engagement. Engagement happens when people are surprised. Surprise happens when people come across new apparent "infor

Facebook and other similar systems reward engagement. Engagement happens when people are surprised. Surprise happens when people come across new apparent "information". New information is most easily propagated through the use of lies. It follows pretty clearly. If they don't want divisiveness, they have to either step away from rewarding engagement, or they have to stop people from lying. They're in a bind, except it's society that is bearing the cost.