Umm.. hopefully we can agree to cut out with the "high school civics" and passing it.
If he didn't pass, he wouldn't have a high school diploma would he?
It's slander that isn't necessary. It's like telling Robert Heinlein, you look like you don't have a degree in english literature, so I'm going to dismiss your work on that presumption.
Telling each other to back off might not work in the long run. The problem delves deeper into misunderstandings and disagreements between both individuals.
Once topics keep coming out that either don't agree with, the problem will start itself once again. It'll be trying to contain themselves in anger until they finally cross the line.
Short term solution.
It will require more further thinking to think of a real compromise.
However, I can throw one of mine into the mix.
When Liebling posts news articles, she can provide her thoughts on both sides. Ie, stepping outside to see the overall picture and understand why both sides have separate thoughts and note them in the original post. That way Jiro won't be out to start correcting her for not realizing something, since she already stated it herself.
Jiro doesn't post much of the news articles, he's more of a patrolman. So the main issue is to solve what's causing him to turn on the sirens. Hence.. "Domestic Dissent".