Facebook surrendered it's right to discuss such things privately when it's willfully kept lax policies on sharing users data. Stuff like this should leak earlier so we can talk about it before, rather than after, awful things happen.
You inspire this sort of debate by thought exercise and ask about actual application - you couch the conversation to direct your staff to stronger ethics.
If this conversation were at Uber, in their self driving car division the consequences of this would be human life. The way to have that conversation, with context would be to couch it in the "trolly problem" - because that would keep the framing.
Ethics, the word is ethics - Facebook is clearly lacking them. Were "dumb fucks" according to FB's chief - and the fish rots from the head down.
And the staff's response "find the leakers" -- funny how many groups of people I find despicable seem to chant this.
It was a case of starting a debate by voicing an extreme opinion.
The memo is exactly and clearly telling employees what to think and do. No questions allowed.