I don't know if trying to define their rule book is a useful approach.
The big difference I see is that most left wing journos (at least the ones being criticised here) are playing a totally different game to the right wing ones.
The Left wing aren't playing a game, they're fighting a war in which they are the righteous . They genuinely don't care about truth or facts. Not as valuable things in themselves anyway.
It is possible to be a partisan journalist, while still being honest and valuing truth. But the only one that comes to mind right now from the Left is Nick Cohen . Maybe the Greenwald/Assange leak stuff counts too, and the New Statesman? How the Guardian used to be many years ago.
Whereas most of the famous right wing / alt-right figures still desperately try to argue using facts and logic. I'm sure there are complete liars / propagandists out there but they tend to be on the edges.
Playing fair(ish) whe your opponent cheats is a disadvantage.
But if the Right wing did go down the route of total lies, then there'd y nothing to chose between the sides except what your gut feel inclines you to. So it's bye-bye Enlightenment and back to the standard course of history of power politics, demagogues, and ignorant mobs.
So, back to the original question by the OP. Their rule book is the rule book of total war. Always cheat, always win. Destroy the enemy by any means at your disposal. This isn't a gentlemanly debate society.
Very simplistic argument, and not polished, but you get the idea. Perhaps someone else could re-write it for me
