I'm a huge fan of George Carlin and many of his observations are spot on but it should at all times be remembered that his main mission was to entertain, not to make political statements designed to impact future policy. Yes, there is some hypocrisy involved (people that vote green, drive Porsches and go on two airplane holidays per year) but at the same time he benefits from the caricature, and that is too broad a brush to paint very large swathes of the population with.

If the planet is overpopulated then that is a problem, regardless of whether people observing this fact or reaching that conclusion see themselves as part of that problem, and regardless of whether or not they take themselves out of the genepool to remove the hypocrisy.