There’s an excellent post on the blog Motivated Grammar about the I vs. Me peeve of grammar pedants, quoting a zdnet blog post on writing:

12. I/Me: We had several different takes on this, with one correspondent nailing it thus: “The correct choice can be seen when you finish the truncated sentence: He’s bigger than I am. ‘He’s bigger than me am’ actually sounds ridiculous and obviates the mistake.”

Gabe notes in response,

Now, there’re two questions one should be asking of this explanation. First, can you just fill in the blank? By which I mean, does a sentence with ellipsis (the omission of words that are normally syntactically necessary but understood by context) necessarily have the same structure as a non-elided sentence? There are many different types of ellipsis, so this is a more complex question than I want to get into right now, but the short answer is no, and here’s a question-and-answer example:

Who drank my secret stash of ginger-grapefruit soda?
(1a) He/*Him drank it.
(1b) Him/*He.

…

Summary: Than can work as a conjunction or a preposition, meaning that than I/he/she/they and than me/him/her/them are both correct in most situations. The latter version is attested from the 16th century to the present day, by good writers in formal and informal settings. The belief that it is unacceptable appears to be a holdover from Latin-based grammars of English.

And in the middle Gabe gives an extensive discussion of the history of English grammars on this question going back several centuries with citations and examples. It’s the conclusion that interests me here: that this peeve is a result of Latin-based grammars of English. And this is most certainly true. What’s funny, though, is that if the originators made their claim for English on the basis of Latin, then it is also clear that they didn’t read their Classical languages very closely. They should have seen that both Greek and Latin involve the a similar syntactic alternation as English.

Latin allows for either a ablative of comparison or the comparative conjunct quam. These two examples from a Kent University website (follow the links).

Ablative:
Quintus diutius Athenis mansit Marco,
“Quintus waited longer in Athens than Marcus.”

Nominative:
Marcus fortior est quam Quintus,
“Marcus is braver than Quintus (is brave)”

Likewise, Greek has multiple comparative structures for clausal comparisons and for non-clause comparisons, too.

John 21:15
Σίμων Ἰωάννου ἀγαπᾷς με πλέον τούτων (genitive)
Simon son of John, do you love me more than these?

Its complement alternative would be something like:

Σίμων Ἰωάννου ἀγαπᾷς με πλέον ἢ οὗτοι  (nominative)
Simon son of John, do you love me more than these [love me]?

Or:

Σίμων Ἰωάννου ἀγαπᾷς με πλέον ἢ τούτους (accusative)
Simon son of John, do you love me more than [you love] these?

Greek also allows for the comparative use of the preposition παρά, as in Luke 3:13:

Μηδὲν πλέον παρὰ τὸ διατεταγμένον ὑμῖν πράσσετε
Do not collect more than what is commanded to you

Here the preposition παρὰ is then followed by a infinitival clause. There may be similar prepositional usage in Latin as well, I’m not sure. Also notably for Greek, this function of παρὰ requires an accusative prepositional object, which means it is, perhaps, the closest parallel to the English structure.

Either way, it’s pretty clear that those who created this particular peeve on the basis of Classical languages, didn’t really think the issue through as much as they should have and those Latin-based grammars of English aren’t as Latin-based as they could have been.