You are 100% correct: children from decent, loving homes get kidnapped and trafficked as well -- which somehow feels even more horrifying.

An effective meme -- especially for a billboard, where people won't have more than a moment to take it in -- must be brief, which is why a meme always tells just part of the story. (I, clearly, am not a person well-suited to creating memes; everything leads to everything else and I have trouble shutting up).

Also, I like this meme in part because I believe nearly ALL of the world's man-made problems have their roots in childhood trauma and a lack of love early in life.

No well-loved child grows up to rape or murder, or to tyrannize people in other ways. Well-loved (not over-indulged; that's something else entirely) children become good neighbors and decent human beings; they aren't driven to join cults or to believe bullshit from politicians, celebs, or authority figures. Even actual psychopaths (i.e., people with certain frontal-lobe deficits that prevent full empathy for others) may be less likely to become nightmares if raised in a loving home, especially if they are exposed to libertarian philosophy (live and let live, basically) and, as adults, marry and have children.