The original usage of Gourmand was synonymous with gluttony and excess; while a gourmet might be satisfied with exquisitely prepared micro portions tucked away within an expansive plate criss crossed by a drizzle of ??, a gourmand wants the full stack pyramided to the maximal stope angle.
No, it's an observation that the first primary usage seemed to disagree (not that it did) and so it was observed that the second alt was used by the commenter above
OED has a lot to say about gourmand, Chesterfield in his 1758 letter that you quoted was saying that the Landgrave has a well stocked table .. good food and a lot of it, for he is a Gourmand. Following that Chesterfield example is a 1816 Coleridge extract from Statesman's Man that also about having a lot (but with no talent for preparation) - excess over taste:
Their best cooks have no more idea of dressing a turtle than the gourmands themselves
And, again, the first 1a primary most common usage cited in the OED is:
1. a. One who is over-fond of eating, one who eats greedily or to excess, a glutton.
It's a usage that has morphed in recent times, sure .. but as seen in the OED for a great deal of time the emphasis has always been on the quantity of good food rather than mere quality of good food.
Gourmand still, in large parts of the English speaking world, carries large overtones of excessive eating under the guise of quality eating.
If I were to make a guess, I suspect that in your part of the world some of the French persuasion made frequent reference to those that overstack their plates as gourmands and it has since locally become synonymous with gourmet as the troll escaped them.
Your original “well actually” is incorrect by your own admission. The correct statement is “a gourmand [was] [in some sense] the opposite of a gourmet”.
Not as punchy. I can see why you exaggerated, but as a fellow pedant I can’t approve of the misinformation.
> One who is fond of delicate fare; a judge of good eating. (Cf. gourmet n.)
https://www.oed.com/dictionary/gourmand_adj?tab=meaning_and_...