Given that last election they took large sums of foreign currency for political ads, had representatives in cambridge analitica’s HQ / war room, happen to profit astronomically from increased engagement due to division and disinformation, and their own employees with insider knowledge are also calling the stance out.
It seems wildly strange in that context, when Facebook could easily take the stance that it’s hard and they might not get it right but will try anyway, instead of bogus misinterpretation of free speech that is Zuck’s current stated position.