From Save the Humans:
Environmentalists hate children and want them restricted to two per family, or less. Children are the symbol of the future pillaging of the planet by humans, and the fewer of them exist the better. So much of the economy revolves around children (schools, entertainment, transport, activities, food). Reducing the number of children is the key to reducing the world population.
Well when environmentalists are upset, we humans should be pleased. Happy environmentalists generally means sad humans and vice versa.