You guys are over thinking it. We're not looking for how many deaths are they RESPONSIBLE for, we're looking for how many they ACTUALLY killed. Hitler is responsible for all those Holocaust deaths, and Marie Curie is responsible for the deaths of the Japanese in Hiro, and Naga.
Technically, if you want to delve deeper, Hitler is responsible for every single death in WWII, If he hadn't gone on his Third Reich campaign, then a lot of those people wouldn't have died.
BUT HE DOESN'T GET THE BODY COUNT. (not yelling, just emphasis)
George Bush doesn't get the body count of Scout snipers in Operation: Desert Storm, the sniper does.
We're not counting how many deaths they're responsible for. We're counting how many they took the life of. We're looking for a singular line of causality, He shot he killed. She clawed she killed. He released the air lock, he killed.
For body counts, you need to see in black and white.
If in another thread, you'd like to debate what deaths the Animorphs are responsible for, than do so, you can explain your shades of gray all you like. But here, we're talking body counts. Black and White, no gray allowed.