The difference is between posting "ugh, having a hard time with someone on a project, they're blocking this merge and I don't think it's for a good reason" and literally starting your post with "Behold," linking directly to a mailing list post, and misrepresenting the other person's objections as "sabotage."

I mean when what you're frustrated about is a leader actively sabotaging what you're working on...

Go on?

Then complaining about that on social media is going to sound a lot like "the leader of this subsystem is sabotaging this thing I'm involved with"

Right, and phrased just like that, it wouldn't have been as objectionable. As I said before, the problem is in the specificity and the direct linking to the conversation. I still take issue with the word 'sabotage' being used here, since the person in question didn't do anything except express objections and an intent not to cooperate. Since this was in a context where that person's cooperation is not needed, I'm not sure he sabotaged anything.