Retraction watch: Irish roots of "french fries"?

It's been a while since we had a post in the Prescriptivist Poppycock category. This example is more a case of badly-researched etymology, but we'll take what we can get, courtesy of Florent Moncomble, who writes:

In the May update of the prescriptive « Dire, ne pas dire » section of their website, in a post condemning « carottes fries » (for « carottes frites », as the past participle should go), they contend that the ‘French’ of ‘French fries’ has nothing to do with France but comes from an ‘Old Irish verb’ meaning ‘to mince’.

Sensing that that was absolute nonsense, I debunked the assertion on X in a thread that you can find here.

Specialists in Old Irish on X have joined in my (to remain polite) bemusement. Evidently the Immortels trusted the first page of a Google search and did not bother to actually fact-check this (apparently popular) myth. These are the people, paid with tax money, who we trust the official dictionary of the French language with.

I'm guessing that the « Dire, ne pas dire » entries are not written by one of les immortels, but rather by an all-too-mortel intern. Whoever wrote it, the full "Des carotte fries" advice is:

Le participe passé du verbe défectif frire est frit, mais on le rencontre surtout dans la forme substantivée au féminin pluriel, des frites, ellipse de des pommes de terre frites. Ce nom est devenu tellement courant qu’il tend à faire oublier son origine verbale et que l’on hésite parfois sur l’orthographe du participe : on trouve ainsi des menus où sont proposés des légumes fris ou des tomates fries, quand c’est bien sûr frits et frites qu’il aurait fallu écrire. Cette erreur est sans doute favorisée par le fait que nos frites se nomment fries en anglais. Rappelons, pour conclure, que lorsque les Anglo-Saxons emploient la locution complète french fries, french n’est pas un hommage à la gastronomie française mais une forme tirée d’un verbe du vieil irlandais qui ne signifie pas « français », mais « émincé ».

The Wiktionary entry gives the etymology for "French fries" as

Clipping of earlier French fried potatoes (1856) and French-fried potatoes, potatoes supposedly prepared in the French style.

with a footnote to the entry in the Online Etymology Dictionary, which notes that "The name is from the method of making them by immersion in fat, which was then considered a peculiarity of French cooking", with this explanation:

There are 2 ways of frying known to cooks as (1) wet frying, sometimes called French frying or frying in a kettle of hot fat; and (2) dry frying or cooking in a frying pan. The best results are undoubtedly obtained by the first method, although it is little used in this country. ["The Household Cook Book," Chicago, 1902]

The 1856 citation is to [Eliza] Warren, Cookery for Maids of All Work:

French Fried Potatoes.—Cut new potatoes in thin slices, put them in boiling fat, and a little salt; fry both sides of a light golden brown colour; drain dry from fat, and serve hot.

The OED has the same citation in their "French fried potatoes" entry, but antedates Wiktionary's 1903 citation for "French fries" with

1886  Savannah Morning News  Clam chowder, white fish and flannel cakes, spring chickens, and Saratoga chips and French fries

The "Irish" etymology is Out There, but Laurent Moncomble debunks it:

Dernière étape, devinez quoi, il existe des dictionnaires de vieil irlandais, dont celui-ci, consultable en ligne. Et là, on a beau chercher 'cut', 'slice', 'mince', on ne trouve rien qui ressemble de près ou de loin à 'french'. Au cas où, une recherche dans un dictionnaire d'irlandais contemporain ne donne rien non plus. 'Cut/slice' se dit 'gearr', 'mince' se dit 'mionaigh'…

Last step, guess what, there are Old Irish dictionaries, including this one, available online. And there, no matter how much we search for 'cut', 'slice', 'mince', we find nothing that even remotely resembles 'french'. Along the same lines, a search in a dictionary of contemporary Irish does not give nothing neither. 'Cut/slice' is 'gearr', 'mince' is  'mionaigh'…

He ends the thread by promising

Après, si un·e #gaeilgeoir confirme les dires de l'Académie, je ferai amende honorable.

Afterwards, if a #gaeilgeoir confirms the Academy's statements, I will apologize.

I should note that there's another etymological myth for "French fries" out there, namely the idea that they were first served at a food stand associated with the 1904 St. Louis World's Fair, run by a man named Fletcher Davis who came from Athens, Texas. Davis (supposedly) told a reporter that he learned to cook the potatoes that way from a friend in Paris, Texas. The reporter (supposedly) thought he meant Paris, France, and used the term "french-fried potatoes" in his story.

Given the earlier citations for the phrase, this story (even if true) is clearly not its origin — though I think it's a better myth than the one about borrowing from Irish…