Honestly, from a PR perspective, I’m not sure it’s so bad. Giving honest updates showing Facebook hard at work is certainly better PR for our kind of crowd than whatever actual Facebook PR is doing.
I still think he should be fired for this kind of communication though. One reason is, imagine Facebook didn't punish breaches of this type. Every other employee is going to be thinking "Cool, I could be in a Wired article" or whatever. All they have to do is give sensitive company information to reporters.
Either you take corporate confidentiality seriously or you don't. Posting details of a crisis in progress on your Reddit account is not taking corporate confidentiality seriously. If the Facebook corporation lightly punishes, scolds, or ignores this person then the corporation isn't taking confidentiality seriously either.