And some people just like talking to kids with no other ulterior motive. We have a LTSO like that here in HSV, and a regular TSO. The LTSO just loves children in general; the TSO has been involved with the Boy Scouts for... golly, it has to be, like, the past forty years. Anytime a young boy comes through the checkpoint, he's all about trying to get them to interact with adults on an even level, involving them with knowing what's going on and asking them questions and such.
Me, I just choose to ignore children as much as possible. I don't like them.
However, I recognize that the checkpoint has to be a scary place for a child. Even for something as simple as them coming through the WTMD, it usually goes smoother if you squat down to the ground to get on their level, rather than keep standing and just telling them to come through - even if you're using a gentle or light voice. Getting down on their level makes it not quite as intimidating. It also usually sometimes helps to stick your hand out and say "Gimme five!" because at least the kid comes through the WTMD to smack your hand.
Either way, some people just legitimately adore children, and like to interact with them. I've seen children react the exact same way to a guy in a Goofy costume, and to Santa Clause, to the exact same line of questioning. It's hardly an interrogation; when you want to interact with a child, there's not very much in the way of things you can say to them that they'd know.
I just think you're making a big ol' mountain out of a molehill on this one, and the guy who wrote the story is, too.