I have not, generally speaking, noticed the frequent use of "big words" by a few posters on various sites whom I suspect of possibly deserving of the title ultracrepidarian.
Usually the two do not go together. If you have achieved a "superior"vocabulary, chances are you have also gone to the trouble to achieve the scope of knowledge that is rightly associated with that vocabulary.
Well, I am aware of at least one field where that is not true at all: philosopher. A philosopher memorizes big words that are not used in any other subject, but after his tirade has been parsed it usually becomes apparent that he has not actually said anything.
It is also appropriate to mention engineering, where the hot advice is "If you can't blind them with brilliance then baffle them with bullsnot."