I'm entirely willing to believe that some underpaid TSA grunt looked at the situation and said to themselves, "Oh, it's that guy again. Well, he's no longer making a fuss and he's not getting in a plane, so it's not my business" and walked off, leaving SovCit with a victory. I'm convinced half the "victories" are someone saying, "Oh, life's too short for this nonsense" and kicking the situation down the road in hopes someone else will have to handle the idiots.
Any TSA checkpoint I've been through is a complex maze. No way their child made it through the checkpoint and I doubt they were able to backtrack without being noticed. This person missed their flight because of the phoney baloney ID they tried to use.