One of Foucault's great insights is that reform is constitutive of the founding institution — prison reform is part of prison discourse, not against it; medical reform is part of medicine, not against it. And so I continue this logic: Greenpeace, Amnesty International, etc are part of the reigning discourse of power. They are constitutive of a system that I, for one, would like to alter.
(When I say "system," I mean system: a complex network of forces and institutions working together. A system is not something we can replace — we can't swap socialism for capitalism. It doesn't work that way. I use system to get us into "system thinking," to not isolate this or that — the Brazilian rain forest! the spotted owl! campaign finance! — but the way everything works together.)
In some sense, Greenpeace is a wing of corporate America taxed with dealing with one of the more obvious corporate externalities: pollution and planet pillaging. Nestle, Chevron, Exxon/Mobil: they should be charged with cleaning shit up, with not raping the forests. But instead it's Greenpeace funded by.....you and me (well, not me). Without Greenpeace protecting our forests and air, Nestle would probably deforest the planet and then where would it be: no more forest and no more people. The dead make poor long-term consumers.
Just as espionage is built into the peace process, charities in the US are built into the capitalist, corporate process: they clean up the mess made by the corporations. Which, in turn, allow the corporations to keep doing what they're doing.
Notice that none of these organizations go after corporations directly. Why doesn't Greenpeace et al put their lobbyists to work to take away personhood from corporations? Why don't they advocate for less work hours which, in turn, would slow consumption and hence the pillaging of the planet? Because they are constitutive of the corporate structure. Because they get their funding from the corporate structure. They are the counterpoint to corporate pillaging that lets the whole system keep running.
So I'm not saying do away with Greenpeace. I'm saying do away with the whole kit and kaboodle, including Greenpeace.