I find it baffling you can’t imagine a human engaging in tribalism, a behavior which predates civilization and permeates nearly every facet of human life.
That’s clearly what it is: Stroud views US citizens as “her tribe”, so people attacking them offends her, while outsiders fighting outsiders doesn’t matter.
Further, this also answers the “moral compass” question: they have a strong moral compass, it’s simply aligned to tribal protection, rather than some kind of “universal” ideal, which is precisely what you’d expect from people who volunteered as soldiers in tribal warfare.
or a military selection of psychos... because ability to limit or completely switch off the empathy is one of the characteristics of psychopathic criminals
That’s clearly what it is: Stroud views US citizens as “her tribe”, so people attacking them offends her, while outsiders fighting outsiders doesn’t matter.
Further, this also answers the “moral compass” question: they have a strong moral compass, it’s simply aligned to tribal protection, rather than some kind of “universal” ideal, which is precisely what you’d expect from people who volunteered as soldiers in tribal warfare.