> US impact on the worldwide death toll is often overstated for some reason

It is only perceived as overstated when the second-order effects of its actions are dropped from the count; the actions of the dictatorships backed and installed by the US never seem to make the tally. Kissinger’s (topical) Chinese containment strategy alone is responsible for as many deaths as the Holodomor. See accounts of Vietnam, Cambodia, Khmer Rouge, Korea.

Should proxies, direct actions by those one supports, etc. not count? Who knows, but that always seems to divorce foreign policy decisions from their consequences when we do.