Fair enough, but anyone who’s been around the block on crisis communications knows that you’re supposed to hit the big red “stop all regular communications until we get a fucking handle on this” button.
The defense that this is a scheduled posting doesn’t help their argument at all. It really points to the fact that they were entirely unprepared to respond to an event like this. Like you said — when you’re in the middle of a crisis, there is no such thing as “regular communication”.
It’s quite common that employees are only allowed to share specific information about companies they work for on social media. Atlassian most likely has that power already.