Good writing can take many different forms depending on the situation, purpose, and audience. If the purpose of a piece of writing is to communicate a complex idea to a non-expert, it makes sense to write using clear, simple, every-day language and to use short, uncomplicated sentence structures. Some people mistakenly think this kind of writing makes them look less intelligent because it appears, on the surface, to be easy. Anyone who has had even a minimal amount of experience writing technical manuals, directions, or explanations, however, will certainly beg to differ.
As Suz says, though, literature isn't always about taking the shortest, most direct, route. Playing with words, sounds, rhythms, metaphors, and all those other elements is what makes poetry out of a language and helps us articulate those emotions and thoughts which can't easily be turned into words. In the hands of a good writer, this use of language is a delight, but, in the hands of a lazy, or inexperienced writer, this kind of writing can be a nightmare.
I'd suggest that the kind of pretentious writing you are reading is a clear indication that the writers aren't yet good enough to write in an advanced style; they need to go back to practicing a simpler version. Good writing takes time, effort, and practice, otherwise it turns into the very worst kind which is lazy, pretentious writing.
ETA: And the above is written in my formal, academic style
