I've got no trouble making a distinction between killing someone because of a mistake or even because of negligence and killing someone deliberately because they are writing things that are inconvenient to you. Come to think of it, neither does the law; the law has made that distinction since the middle ages. It calls one of those "murder", and the other something else.
The law doesn't have a specific term for people who just have a callous indifference to the lives of others, but people throughout human history have used a lot of terms to describe such people. Today I will use the term 'scum'.
So, attributing their death to "Chechnya" is a little like attributing a hypothetical murder of Sy Hersh to the Iraqis.
Shorter: no, I think you're wrong about this.
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...