Generally speaking I don't think Britain nor America are known for killing members of Greenpeace. Now if we are talking illegal kidnapping, overseas assassination of alleged baddies, droning, wantonly killing people in random countries etc, then America in particular is a mastermind. However, Greenpeace activists seldom get murdered. You certainly don't lock them up as pirates when they are no such thing. Greenpeace is a resistance to the tyranny of oil and environmental catastrophe and on that basis should not be locked up as if they were terrorists (as if the term means anything anymore). If any nation is guilty of actually slaughtering activists on ships then Israel wins that rather unseemly award. The UK and America generally stick to killing poor Arabs rather than their own conscientious activists.