When I was in university, the introductory class was about Java, and an advanced class in the next semester was about Haskell. There were many imperative/functional newbies in both classes, but the Haskell class still progressed much more slowly. Haskell is simply much harder to grasp, independently of experience.
You can also see this in the fact that even mathematicians use Python rather than Haskell for simulations. Despite the fact that there is no population that is better suited for Haskell than mathematicians.
Even cookbooks are always written in an imperative style, never in a functional one. Why is that? Human brains find imperative algorithms simply more intuitive, and this is not explained by not being used to functional ones.
Religious texts, philosophy, ethics, and even self-improvement books often don't provide a procedure to follow. They teach things like how to handle conflict, how to act fairly, how to navigate difficult situations, or how to reason about competing values.
People then take those ideas and apply them across many different situations in their daily lives. In a sense, they build a toolbox of reusable mental functions rather than memorizing a single algorithm.
That's also why many people finish a self-improvement book feeling like they didn't get much out of it. They were expecting a recipe. Instead, they absorbed a collection of abstractions that only reveal their value when applied later in real situations.
The fact that cookbooks are imperative mainly shows that procedural tasks are naturally expressed procedurally. It's not obvious that this generalizes to human reasoning as a whole.