Zoos are becoming facsimiles - or perhaps caricatures - of how animals once were in their natural habitat. If the right policies toward nature were pursued, we would need no zoos at all.
I think it's great that we have organisations like Greenpeace. In a pluralistic society, we want to have people who point out all the problems that the Earth could encounter. But we need to understand that they are not presenting a full and rounded view.