I think people get angry for a number of reasons, guilt could be one of them.
In some ways though, the whole green thing has been portrayed as two polar opposites: either a straggle-haired, beardy, sandall-wearing hippy grubbing out a living or a gel-haired, sharp-suited executive drinking in expensive wine bars, whereas, in fact, there are lots of ways to reduce one's impact without turning into the former (unless you want to, of course).
A problem is that many societies measure worth by possessions, big house, big car, fancy watches, exotic holidays. Thus lower impact items and pursuits equate to a loser, an unsuccessful (and maybe even stupid) person.