For what it's worth, the author is well-known in the field of programming languages and was a professor in that area at the University of Utah for a number of y

For what it's worth, the author is well-known in the field of programming languages and was a professor in that area at the University of Utah for a number of years before changing life focus and relocating to the University of Alabama's Precision Medicine Institute. Which isn't to say that you're wrong, but rather that the author is likely well aware of these particular shortcomings of the exercise. But then the exercise wasn't "write perfectly idiomatic code in a different language every day", but just "learn some languages I didn't know before".