Why do philosophers use highfaluting language?

It all depends on what you mean by ‘highfallutin’. Name a couple of them, and what words bother you?

That "one scholar" is correct. Not only that, EVERY  discipline has it's own vocabulary, not just Philosophy. All disciplines also require an understanding of the basics before you can move on to more complex ideas. Do you know what  "intersaltation collision" or "Euler space marching" mean? Unless you are an aerodynamicist, I'd guess not. To sum up, the problem is you, because you weren't interested enough to learn the fundamental terminology.  

Firstly, observe or recall your already-held conclusions regarding specificity.  You understand that a loaf of bread = a loaf of bread, an atom receiving a specific quantum of em energy will evidence a raising of an orbital within it, etc.  These are specific.

These event sets are not unitary, but subject to various levels of specificity, such as "There is a loaf of bread, "There is a loaf of freshly baked bread ("fresh" e.g. being defined as "at least one degree warmer than normal room temperature")," "There is a loaf of French bread," "There is a loaf of whole wheat bread priced at 10% below regular store price for its kind because it is a day old," etc., etc.

A down-to-earth genius, like Richard Feynman was, might say that if one knows the granular or technical specifics of quantum mechanics, one may describe the "quantum loaf of bread" mathematically, and analogously or poetically for those who a) cannot know to do the work and b) who are reasonably intelligent lay people able to read words with comprehension, such you have doing during this period of reading.

A simpler summary:  It is what it is, a loaf of bread, an energy process, etc.

That's user-friendly, but not so much producer-friendly.  To the producer, "Make two of these high-protein, seven-grain loaves from scratch for tomorrow" requires more specific "language" (words as conceptual directors and meaning-holders).

Using words in less-controlled or less-atomistic processes tends towards fuzzier or less-clear axiomizaions.  One horrific example has been the infantile or spoiled consumer who has failed to learn what specialization means--specialization being an increasing yoking to a precise energy process, be it shoe-repair or meditation--and who thereupon "jump the shark," typically either in egoistic/psychologistic projections such as "producers too withholding/controlling/unfair" and/or "when society becomes fair and just, all means of production will be baby/amateur/noble-savage friendly, we'll all just go from farming to building to fishing, like the noble savages did before use of capital began to build factories of complexification."

Such opinionated fuzzy axiomization increases "exponentially" in the softer sciences, and even more so in philosophy and the arts.

You likely understand this, as most people do:  "Piled high and Deep" is particularly germane to much "PhD" "gradgrinding" in "Studies" and Critical Theory" programs, Sociology, Lit Crit, and even in Philosophy :-) 

Moving into more precise areas such as bread making and quantum physics, there is amazing yoking, specificity, and precision.

So, in fine, the fuzzier the axiomization, the higher the "bs" level, including use of words/language.

Related:  The Slightest Philosophy by Quee Nelson;

Understanding Yourself by Mark Prophet;

The People of the Lie by M. Scott Peck;

A Warrior's Path by Robert Trivino.

It is possible to use the concept of functions to describe more than just how lexical meanings work: