I feel like after Google's recent blunder, Facebook might have thought about toning it down a bit. If anything, Facebook had a "Hold my beer!" moment.
It's pretty common place for a website to have policy against inciting violence. Facebook added an if clause. You can incite violence if it's a violent person, a hate group, or someone Facebook doesn't like.
I don't need to say anything more, go ahead and read it straight from the horse's mouth.