From some FAQ on Greenpeace USA’s website:
Don’t the deniers have a right to free speech?
There’s a difference between free speech and a campaign to deny the climate science with the goal of undermining international action on climate change. However, there’s also responsibility that goes with freedom of speech – which is based around honesty and transparency. Freedom of speech does not apply to misinformation and propaganda.
Well, I’m sorry, Greenpeace USA: I, for one, will continue to support Al Gore’s right to speak out.
The one and only.