This is a national security issue. That seems like the most pertinent issue, and yet there is no mention of it in the discussions here. Facebook has amassed huge amounts of data about all citizens, and adversary nations are leveraging this data to manipulate the nation, including by helping elect a president who will be friendlier towards them.
Facebook is Russia's biggest cyberweapon. Just as private companies would not be allowed to stockpile WMDs, private companies should not be allowed to stockpile so much digital information either. This is a national security issue.