Your assumption of pure motives from a "non-profit" advocacy group is unjustified. The management of "friends of the earth" get paid too, and the more donations they bring in the more secure and comfortable their position will be. They have direct financial interest in motivating donors with urgent calls for action.
Remember that the only difference between for profit and so call "non-profit" enterprises is that the former has a class of people ("owners") who have a claim on their profits. Non-profits must bring in the dough to continue in operation just like a for profit business. The real difference is that, without owners, those in control of non-profits have more latitude in directing the resources of the enterprise to their own benefit.