Greed isn't inescapably "human nature", but results from it under some basic conditions. The nature of enjoyment and suffering means the pursuit of enjoyment and avoidance of suffering as a biological imperative. Desperation, lack of cultural/learned empathy, cultural normalization of disparity, etc., can quickly allow unchecked greed. The same thing, with different conditions, can be said for... not sure there's a single word for it, but behavior motivated by empathy promoting equality and sharing and so on. The conditions actually kind of close to being the inverse of those for greed - some combination of not having desperation, having cultural/learned empathy, cultural normalization of economic equality, etc. Both types of thinking are just basically pro-social or anti-social thought with regard to material/economic gain, depending on what influences individual thinking.