Urgh, it is basics of coding course for 8 year olds. What do people expect? Albert Einstein giving lessons?
If the 8 year olds are really encouraged to explore and ask questions (vs 'jump through these hoops, follow instructions), the staff at apple will most likely be unable to answer their questions.
I would say that most adults are often simply unable to answer those questions because they just don't know. Children are naturally curious to levels which exceed the average adults ability to answer. Even educators are often inadequate to the task, if the question falls out of their areas of study. Some educators try to condition their students to focus on the limited prescribed domain of 'material they are to learn' and not ask questions that cross outside of that domain - in part to avoid acknowledging their ignorance.
But I would go further and say that children often also ask perfectly reasonable questions beginning with "how" and "what if" which stump adults. You can see this very readily when the topic is anything related to the natural world, as most adults are ignorant of basic science.
Teaching neophytes (and, especially, neophytes who are also children) the basics of anything -- especially in ways that will engage them and not leave them both without knowledge and with less interest than when they encountered the teaching -- takes nontrivial knowledge of both the subject field and teaching methods.
http://www.worldofspectrum.org/books.html
So if 8 year olds could grasp Basic, Z80 and 6502 Assembly, I guess adults in a computer shop should know their stuff.