You're essentially describing the equivalent of online fascism, neo-Nazi down voting brigades sound suspiciously close to Meatspace Greece at Present.
Any system that mimics democracy, even with active moderators, will succumb to a large enough minority of trouble makers. If they really are a marginalized group that does not represent a significant percentage of the community - even with all the tricks and manual puppet accounts and all the real world parallels - they will remain marginalized. If things turn dark that easily one sadly suspects it has more to do with the flaw in the algorithm of the people rather than the system.
As for programmatically doing what you claim, that hasn't been demonstrated. I'm pretty sure spammers have even more incentive and resources and yet the volume of spam is manageable still.
It just shows the old principle that small, organised groups can impose preferences on a disorganised majority. It's a predictable phenomenon in collective decision-making systems. If I understand the economists correctly, it can't really be "solved".
Any system that mimics democracy, even with active moderators, will succumb to a large enough minority of trouble makers. If they really are a marginalized group that does not represent a significant percentage of the community - even with all the tricks and manual puppet accounts and all the real world parallels - they will remain marginalized. If things turn dark that easily one sadly suspects it has more to do with the flaw in the algorithm of the people rather than the system.
As for programmatically doing what you claim, that hasn't been demonstrated. I'm pretty sure spammers have even more incentive and resources and yet the volume of spam is manageable still.