People have different motivations for using gobbledygook instead of plain language. They may wish to sound impressive and assume, incorrectly, that fancyisms trump familiar words. They may use it as a technique of avoidance or obfuscation, if they want to hide the truth or are unsure of what they’re talking about. Or it might simply be habit or convention, as I said of advise in business communication.
Don Watson elaborates on this in his admirable polemic Gobbledygook: How Clichés, Sludge and Management-Speak Are Strangling Our Public Language (US title: Death Sentence: The Decay of Public Language):
Corporate leaders sometimes have good reason to obscure their meaning by twisting their language into knots, but more often they simply twist it out of habit. They have forgotten the other way of speaking: the one in which you try to say what you mean. Instead they welcome their audience and proceed immediately to put them in a coma by announcing their intention to spend the next half hour outlining the company’s key strategies and initiatives going forward, and their commitment to fill capability gaps and enhance sustainable growth for the benefit of all shareholders…
Even when we use it as a shield against our own uncertainty, pompous language is a weapon, an expression of power. Part of it is a mistaken effort to elevate the tone. Beneath pomposity rests the assumption that she who elevates the tone will herself be elevated; with luck, beyond scrutiny. The risk, which the truly pompous never see, is that an opposite effect is achieved or the tone moves sideways into unselfconscious parody.
On the matter of saying what you mean, Tom Freeman describes a writer going into Writing Mode instead of just putting their ideas in a direct and ordinary way. This is a common problem among aspiring or unskilled writers: they strive for impact in all the wrong ways, such as packing their prose with overelaborations and formal synonyms. Whether through habit, naiveté, diffidence, or lack of faith in simplicity, the result for readers is the same.
Two other things worth mentioning in brief: You probably noticed Watson’s use of she as a generic pronoun – throughout Gobbledygook he alternates between she and he for this purpose. A few writers do, and while I would favour singular they, the alternating style is at least more equitable and inclusive than defaulting to he, as too many writers continue to do. And did you see that unhyphenated unselfconscious? I approve. Oh yes.