This is a very interesting dilemma.
I was just talking about such a thing with a well-known Rabbi who said the main reason people should follow a hechsher and not rely on ingredients is that you need a degree in chemistry to know what is kosher or not.
He stated when he was a child, though, yidden could go into a gentile bake shop and buy bread which was kosher by the fact the ingredients were very basic.
It is very possible this girl had a parent or grandparent look into the matter, and the ingredients were merely cocoa, sugar, and some other very basic ingredients which are known to be kosher. Many organic foods are very basic like that.
What adds to this confusion, for me, is how the question of Slurpees being kosher from kashered or not kashered machines, especially if a dairy drink was stored in the very same “compartment” was ruled as not being an issue due to something about the machines and dairy being so negligible that it does not threaten the kashrus status of Slurpees. To me, even though they are correct, it appears as a loosening of standards.