That's an interesting way to think of it; that the anti-building folks are just yesterday's hippies, having grown older, more moderate and self-interested.
Another way of looking at it is that political movements are coalitions. Sure, people who are really concerned about the environment and people who are really concerned about poverty and the welfare of the poor are both on the left of the political spectrum in America, but they are not really natural allies; those in poverty use a lot less resources than they would if they had middle-class incomes, and things like organic food are massively less efficient, meaning that choosing organic food, to the extent that it crowds out inorganic production, is raising the price of food, something that is largely irrelevant if you primarily care about the environment, but central if you primarily care about the poor.
(Of course, there is some agreement, I mean, the price of farmland forces the issue, but 'sustainable farming' is important for all; you don't want another dust bowl, but that's a problem that, from my understanding, is largely solved, outside of, say, cattle grazing on public land. No farmer wants to destroy the production capability of his or her land. )
I mean, I'm certain that was a biased example, but my point is just that there are a lot of competing interests within a particular political coalition, so quite often, apparent hypocrisy is simply the fact that different people and different sub-groups within a broad political movement have different and sometimes conflicting priorities and values.