Self-righteousness as Psychological Symptom
As described the study seems a bit lame. I'd say - without having read the study itself - that people who become organic snobs would become some sort of snob anyway and that eating organic is simply their excuse. Does eating organic cause people to be jerks? Probably not. More likely it allows them to exhibit jerky propensities that they'd exhibit in some manner anyway. And I'd bet the food snobbery is correlated with rigid, judgmental behaviors on other dimensions too! (You know, 'I drive a Prius. And I don't just do yoga, I do this very, very strict sort that everyday lame-asses cannot possibly appreciate!' and so forth.) These are people who would've been Dana Carvey's 'church lady' in some other milieu but happen to have ended up at the food coop instead. I see it pretty much every time I go to Advantage Food Coop or out to visit August. His home town is full of this sort of moralistic acting out.