I think maybe part of it is that most people are introduced to FP through haskell, if I had to guess. And haskell (at least the tutorials) is IMO guilty of the top-down approach where the final value is written first, referencing variables that haven't appeared yet. ocaml, on the other hand, has you define your components before the final value which is more familiar to most programmers

I think haskell doesn't always look super readable, but I can appreciate it at least because it reminds me of math papers where the final theorem is introduced first, and then it's broken into lemmas, and each of those lemmas is proved etc