This is exactly why I think he was wrong. Normally, pretty much everywhere else we use the terms, "positive" denotes the presence or addition of something, while "negative" denotes the absence or subtraction.
So while I agree with the GP's comment that Franklin didn't know anything about electrons, so he arbitrarily picked one as negative and the other as positive, now that we do know about the movement of electrons, it kinda sucks because I think Franklin just "picked wrong".
I.e. it would make much more sense to me if the absence of electrons (i.e. holes) were negative by convention and an abundance of electrons were denoted as positive.
This is pretty much spot on. It sucks after 250 years of hindsight, but I would encourage anyone who wants to think like Franklin to buy an amber rod, a glass rod, a piece of real fur, and a piece of silk, and try experimenting with them and see if you can intuit from physical experiment what the fire is made of and how it passes from one material to another. You can't without the benefit of future knowledge.
This is what it feels like to stand on the shoulders of giants.
In semi-conductor design discussions around transistors and motion of electrons, it’s often much more convenient to talk about hole (bubble) migration than electron migration.
It’s really a moot point as to whether the abstraction used to solve problems matches with the physicalist interpretation of reality.
So while I agree with the GP's comment that Franklin didn't know anything about electrons, so he arbitrarily picked one as negative and the other as positive, now that we do know about the movement of electrons, it kinda sucks because I think Franklin just "picked wrong".
I.e. it would make much more sense to me if the absence of electrons (i.e. holes) were negative by convention and an abundance of electrons were denoted as positive.