It's the specific context around this photo. Vietnam was defined by media presence which was what drove public outrage against the war.

Essentially the thesis is this: if Facebook were the dominant media platform during Vietnam, we never would've seen these images; we probably would have continued committing atrocities against civilians and our own soldiers.

Seeing as we are now involved in several wars around the world, if our media cannot publicize the realities of war because a child's clothes got blown off with her legs, then someone (i.e. Facebook) has a stranglehold on public opinion.