The history of that quote is actually older and much more interesting.

https://quoteinvestigator.com/2010/05/21/death-statistic/

That would be bad enough, but I expect the salience of Khashoggi's murder has more to do with identity than numbers. It's not as if a singular dead Yemeni child would have dismayed anyone in the West. What made Khashoggi stand out was that he was a WaPo journalist.