You went to Stanford and have never seen a Trie in highschool? There are a few highschools in Bratislava, Slovakia that teach basic data structures in their Intro to programming courses.
The end result is that university CS programs are run with the assumption that highschool students had zero prior experience with programming.
There's a reason that so many software geeks are hardcore libertarians and Bill Gates was fighting to reform teaching into a meritocracy - the educational system basically ignored their core skill-set and so the students were often self-taught. Obviously schools are playing catch-up now, but you can't change the past experiences of two generations of programmers.
Oh how times have changed.
In secondary school ("high school"), The only computer subject they taught was IT, and people weren't allowed to take it unless they had a special reason not to take a foreign language. It was rumored to be ridiculously easy.
The UK is supposed to be bringing in a programming GCSE - I'll believe it when I see it.