@derp Two things going on there, the White Knightism, and the Only Killing is Winning.
It's been said before, but few players want to see their characters as the truly bad people, AND many people are adverse to "starting something" first. So they play the nicest vampire who ever had to murder an innocent because well they didn't want to, and if this one didn't die, many more would have to die later. And you know those vicious faction enemies, well they exist no matter what, and you can't fault their players for wanting to be on the grid. And there might be peace based on assured mutual annihilation.
Until The Incident.
Then you have unleashed the Hounds, and the more people are involved the more likely the path of Final Victory will be selected, and achievable.
I'd say make it pay off more to be more diverse forms of bad, and to hold relationships with entities you don't like. And then damage your goals when something you (unhappily) relied upon falls apart. Chaos happens, new players arrive who don't have sustainable goals. More is lost. Etc.
That's right, don't fix a social problem with code, fix it with game systems and story. TAKE THAT Tweed Robot!