I don't think there was any "one true way"-ness in this article. It described a different way to write programs, and argued it's better. Don't let the use of the word "pure" fool you, I also expected an argument about "pure" functional languages vs mixed, but it was not the case. Pure programming, in this context, means locally side-effect free programming, using immutable data structures. It said nothing about using imperative programming in other parts of the software, or even about using non-immutable variables inside a function.
