Quite the opposite. Functional style is especially useful in larger codebases. However, I think a functional strongly typed language is often easier to get right than a weakly typed one. I mostly write F# and Clojure and based on my experience I would go for F# any day over Clojure but at the same time I would also go for Clojure over Java as well.
I do not know where your views are coming from, sounds like 2nd hand experience rather than 1st one.
As I stated in the beginning I do not work with Clojure. Pure functions is something I use in any programming language. I have a hands on experience from a lot of different functional languages though including F#. From what I understand it is very common to use context based style of coding in Clojure. That is at least what I heard and Google does not seem to disagree...
I do not know where your views are coming from, sounds like 2nd hand experience rather than 1st one.