Part of the never-ending quest
to fight pidgin Latin
and other languages incorrectly used. The above argument doesn't really fly, but it's as good a nodeshell as any under which to write this.
The first thing to recognize is that, until recently, written works have always been years behind vulgar speech. Everyone, sometime during their career, should have had a teacher telling them what to avoid in papers: no neologisms, no dangling participles or prepositions, no split infinitives, and so forth.
This hair-splitting pedantry is an ancient thing; Mesopotamian schools already existed to teach proper Akkadian grammar and writing, and Greek schools taught the virtues of the Attic and Asian styles of rhetoric. But the clearest example is the rise of grammarians in the Roman empire. They maintained the self-imposed task of defining good style, in its basest form simply teaching what is effective and what will fail for the purpose of persuasion. Applied to English, some of this is common sense. A simple example: if you would like change for a dollar bill from a kindly store clerk, you do not walk up to her and shout 'yo, bitch, gimme four quarters'.
So why this army of historical pedants? Are they nothing more than the right arm of the man, oppressing your right to speak and write incorrectly? In the case of the Roman grammarians, they were guardians of language. They rose at a time when the empire was falling apart rapidly, and spreading across Europe and the mediterranean, assimilating all sorts of languages and cultures. Defining good Latin meant creating linguistic unity and stability.
How different is this today? Defining an American is close to impossible. Our culture is rapidly expanding, especially through the internet, with a huge range of opinions and thoughts. Good Latin is a trivial example, but correct grammar is a unifying force, beyond just a prevention of the dissemination of incorrect information; that it is a dead language also gives no excuse for using it incorrectly, since grammar is fixed, and won't mutate further.
English is trickier; modern theory says that writing should reflect the spoken word. Poppycock. If I wanted that, I'd listen to you speak directly; beat poetry falls apart when you're no longer listening to it. But it's arguable to what degree a linguistic peculiarity is really an error.
The point? Latin is good. Latin is great. So are the hordes of other dead languages, used too often to make an idiot sound impressive (case in point?). If you use it, use it correctly. Somebody here is going to notice (probably people like me, who don't too often point it out), and you'll look like a fool.