"I certainly would not put Q = U x A x (Ti-To) in an essay written for broad consumption and then criticize someone for not looking it up themselves. Q=UxAxdeltaT is just as obscure to a non-engineer as some Latin phrases are to me."
-- from the same reader

No. And I wouldn't either. Nor would I use just any Latin phrase that came to mind. "Eheu fugaces Postume, Postume" can appear in "Speak, Memory" but might be out of place in an Op/Ed article. But the phrase "fortiter in re, suaviter in modo" has been in common English usage for centuries.

Some knowledge of mathematical formulae can be assumed, while much cannot. A lot depends on the size, and level, of the intended audience, and even where that audience may be. An Italian journalist can put all kinds of Latin into his Italian, and cheerfully assume he will be understood. A Russian journalist can put all kinds of scientific formulas into his articles for the popular press, and ditto.

In this case I thought, and think still, "fortiter in re, suaviter in modo" was perfectly appropriate, and it did not make unusual demands on readers. You disagree. Therein lies the quarrel.