Something you might consider is a rule that "detects" this behavior--if they move back far enough, late in the game or whatever, you call it an automatic resignation. I apologize for not having a precise definition--you might need to playtest it with a group and have someone play the vindictive, atmosphere-ruining jerk [oh, sorry, was that phrasing judgmental? :) ]. Basically, the idea would be that you could calculate that they are actively hurting their final standing, and take that as a trigger for automatic resignation.
Either that alone. or that with two votes by other players that someone is using that anti-strategy could be enough to declare a house-rules resignation (either kicking them out, or preventing any more money collection via that method for the remainder of the game). Even without an exact numerical standard, you could have a two-vote rule.
Finally, something you could do is change your viewpoint and consider the original behavior you're objecting to here to be a valid meta strategy. I have a son that plays like this--if he perceives that you have slighted him in a game, he will make the rest of the game be about hurting you back. It's like the way poison dart frogs have evolved bright colors to let predators know that they are dangerous to eat. People know this is a strong possibility and avoid singling him out in any obvious way.
This is a serious suggestion--if you can view it with amusement or appreciation as a meta strategy, it might be something you can laugh about rather than be irritated by.