Perhaps there's a size limit on embedded non-edible components.
King cakes are another example — commonly enjoyed despite how many baby Jesuses have been swallowed or choked on.
(1) has partially or completely imbedded therein any nonnutritive object, except that this subparagraph shall not apply in the case of any nonnutritive object if, in the judgment of the Secretary as provided by regulations, such object is of practical functional value to the confectionery product and would not render the product injurious or hazardous to health
Since hidden pillars are neither hazardous to anyone's health and also provide functional value, seems like they'd be just fine.
Thanks for the research.
At this point I guess it would be helpful to know the letter of the law/regulation, but it's also probably not important enough to bother.
Do big American Easter eggs sometimes come with plastic bags of smaller candies inside? Those seem less likely to be a choking hazard, but similar enough that they could fall afoul of the law that hits the Kinder eggs.