The analogy should be clear. There are children whom I can save by donating large sums of money per child to get them mosquito nets? Why am I on the hook for this? This will never end. Are there not more systematic ways of dealing with the whole situation? Some sort of mosquito-net mass production program? Eradicate the mosquitoes somehow? Stop having children?

Relevant parable: The Upstream Story.

Does GiveWell take "acting upstream" into account in its assessment of charity effectiveness?