Who knows, it might have conferred a survival advantage in our distant past--bands of nomadic hominids might have had to kill and even eat each other at times.
A number of early European explorers (including Champlain, if memory serves) describe ritual cannibalism--generally the consumption of prisoners, who were first tortured to death in that holistic and natural way First Peoples had--but also describe people starving to death in times of want without resorting to it.
In the case of this woman, her amygdalae have been damaged by Urbach-Wieth disease, which according to the article is extremely rare.
That said, it is likely that there is a wide distribution of various types of emotional response in the populace due to variations in neurological capability.
How is this not a contradiction in terms? Non-political humans seem impossible.
Perhaps they fail to empathize or sympathize with their "future self", which is who they view as the recipient of whatever it is they should be scared of currently.
Though of course, IANAP.
Or maybe it's our turn (the homo sapiens who have fear) turn to die out, letting more fearless ones take place. Although, this sounds more of a fictional novel waiting to be written.