If I have to be "interrogated" every time I travel to the US or Canada fine, if it means they prevent one child from being trafficked or whatever.
What if it prevents no children being trafficked?
Do you have reason to believe that children are, in fact, being "trafficked" into the USA on commercial transatlantic flights? Ever? It seems awfully complicated, with passports and tickets and shit, when there's a porous land border into Mexico.
There are children who are the subject of custody disputes being moved over borders, and the Hague Convention exists to deal with that. Children are checked at borders because of that, particularly if there is reason to believe they might not be the children of the people they are travelling with. But that's not trafficking, and there's no suggestion that the Irish police were worried about the Hague Convention (aside from anything, a DNA test would prove nothing, as in most custody disputes the child would match the parent with whom they were travelling).
But the claim here is about dastardly (dark-skinned, of course, a generally a little bit foreign) abductors taking innocent white children for nefarious purposes. It's essentially 1950s tropes about innocent women being lured into the white slave trade by West Indian men with their devilish jungle music. And about as convincing.