I don't think this is true. I think Haskell's notation is the way it is because it emphasizes the "look" of certain abstract patterns that would be obscured by the notation used in other languages (I believe this is the case for math as well... I doubt it's that way for hand writing speed, since I doubt that's the bottleneck in maths). This is not what many of us who come from other programming languages are used to, and therefore we identify it as "more difficult", but it actually is lack of familiarity. Not only with Haskell itself, but with the abstractions and the way of looking at programs.
I doubt the majority of Haskell programmers would prefer a more verbose notation. I think that, like the parent post, they consider Haskell very clean and readable.
A friend of mine who is a proficient Haskeller told me he often struggles to understand new Haskell libraries. Then the library "clicks" for him and he can begin to use it. I -- who program in Java for my day job -- have trouble understanding this, because this is seldom the case for Java: you may not understand what problem a Java library is intended to solve, but using it is usually trivial (and mis-using it is trivial as well, of course!). I think it's unfair to compare both languages this way, because in Java there is a fairly low use of general abstractions, and Java's syntax (and coding practices) have evolved to reflect this. The verbose syntax that works (1) for Java is not suitable for other kinds of programming.
(1) for some values of "works".