I still think when Russell says "neutral third party" he means "unemotional third party" as in, if Hardin where looking at things objectively, he'd OBVIOUSLY tell Null to settle because it's in his best interests, so if he keeps fighting it he must just harbour a personal hatred of Russ that's overriding his judgement.
I suspect he gets this perspective from his lawyer in the Erika stalking case telling him to never talk to her, only go through him because he's an unemotional third party, and take the guilty plea because it's the best you're gonna get