[jmd42]

I'm on the same page.

Sure, your day-to-day work may not involve manipulating binary trees. But presumably it does involve working with variables, objects, references, manipulating data of some kind... And if you're comfortable with the fundamentals of those, then this is something you should be able to figure out even if you've never heard of a "binary tree" before, once somebody has sketched it or shown you the definition of their TreeNode class, right?

It honestly baffles me how people consider this something which needs to be drilled or memorized.

There are absolutely algorithmic questions which would fall into that category. But if somebody considers this to be one of them - or something like "find the smallest number in an array" - then I have to question whether they have an understanding of the most fundamental concepts in programming...

Or if they get through each day solely using things they've memorized by rote, or looked up, and they don't really have any idea how any of the foundations they're building on actually operate.