There's a nice writeup describing the simplicity of Haskell syntax. [0]

  Haskell has 21 reserved keywords that cannot be used 
  as names for values or types. This is a relatively low
  number (Erlang has 28, OCaml has 48, Java has 50, C++ 
  has 63.

In particular, some of the operators you mention represent such fundamental and common tasks that it makes sense to have a shortened form. I'm in agreement that descriptive names are preferable in general, but not always. Haskell syntax is quite simple and predictable (I say that as a former Rubyist); it only appears strange in the beginning because there are so many new concepts to learn.

[0] https://github.com/kqr/gists/blob/master/articles/simple-syn...