Is there some cultural convention in the US that I don't understand whereby murdering (white) journalists is really really wrong and never possibly justifiable but murdering (arab) children is a perfectly acceptable part of the rough and tumble of geopolitics? Otherwise I don't understand your narrow focus on journalists.
As an aside, it's not like the US never deliberately targets journalists: https://en.wikipedia.org/wiki/Al_Jazeera#Death_of_Tareq_Ayyo...