Well, then those that die gave their lives for the cause of preserving whatever DDT was threatening. War is hell, and all that.
IIRC it was the eggs of some bird.
The issue when they banned DDT was the claim that it caused the shells of eggs to weaken and that bird species were going extinct as a result.
Later evidence is that not unlike the Climate Change crowd they pimped the data (choosing birds in areas with calcium deficient diets to study).