> So a "rational" actor in economics seem (to me at least) to mean the typical selfish bastard
Well, a rational actor works to maximise their personal preferences effectively. You've accidentally slipped an assumption in that all people are fundamentally typical selfish bastard's with a corresponding set of preferences, but I suspect you don't actually assume that personally because of the invoking of green warriors.
A green warrior or charitable giver is still a rational actor, and adequately modeled as a normal source of demand. It just happens they need to be acting rationally in context of a larger system to themselves or basic law-of-the-jungle style effect will optimise them out. Green warriors themselves often talk about preserving the planet so people can live on it, which is clearly a personally rational goal. Charitable people will often say similar things.
Well, a rational actor works to maximise their personal preferences effectively. You've accidentally slipped an assumption in that all people are fundamentally typical selfish bastard's with a corresponding set of preferences, but I suspect you don't actually assume that personally because of the invoking of green warriors.
A green warrior or charitable giver is still a rational actor, and adequately modeled as a normal source of demand. It just happens they need to be acting rationally in context of a larger system to themselves or basic law-of-the-jungle style effect will optimise them out. Green warriors themselves often talk about preserving the planet so people can live on it, which is clearly a personally rational goal. Charitable people will often say similar things.