[zodiac]

I think the author somewhat explained why FP "suggests" that. In his explanation, it's because when you read tutorials that operate on "numbers and strings and simple lists" (as the author puts it), you do create and destroy those structures willy-nilly.

So when you operate on a large array (as in his example), a natural approach is to also create and destroy it.

Of course after you gain experience you learn not to do that, and techniques that let you not do that, but I don't think he is missing the point.