I feel like your post focuses too much on the present memes about what people in the 21st century believe about medieval believes about witches instead of what people back then believed. The Survey of Scottish Witchcraft for example provides a lot of information about witch trials and from them I don't get the impression that it was about a very narrow class of people.
https://en.wikipedia.org/wiki/Flying_ointment. suspect the witch hunts started as ordinary "state wants to control the jollies and/or keep subjects from hurting themselves".
it sounds very scary to see that woman and hear her screaming.
That's an interesting observation. There are certainly enough news stories of similar situations that I could see a narrative around witches being real emerging in a society that didn't have CAT scans to diagnose them and believed in the supernatural. Quite a few 'True Crime' podcasts could change a few terms around and become fire and brimstone preachers, revealing evidence that the devil's agents are amongst us.
I think another element to it is that there are people out there who are genuinely so evil that it's difficult for normal, healthy people to model them, or even believe that a person had done the things they've done. The distribution of their behavior diverges too greatly for them to register as human. Ghislaine Maxwell, if shown to a medieval peasant, would definitely get filed in the 'witch' or 'satan-spawn' column.
There are certainly enough news stories of similar situations
Are there? I don't recall any of the, say, Salem witches as being mentioned as routinely going around and spewing insults and curses like OP's example (correct me if I'm wrong). And if it's infertile women, why were so many men accused of witchcraft? And why do description from many places about 'sorcerers' or 'shamans' being lynched by their tribe emphasize the sinister secrecy and normalcy of the poisoners who finally received justice? (You mention Maxwell - I am not an Epstein enthusiast at all, but if Maxwell was going around all those yachts and hoity-toity parties or supposed social media profiles spewing curses and maledictions at a level that would make someone with Tourette's blush, I have certainly missed any coverage of this.)
If anything, cases with such overt obvious illness probably makes them less likely to be accused of witchcraft, because they are so obviously 'touched' and nothing they say means anything. Why indeed would Satan wish to recruit as his mortal pawns such foolish inept loons who cannot so much as keep a civil tongue in their head while going about the more important business of spoiling the milk and attending the black masses?
I don't specifically mean spewing insults, and I doubt OP did, either. It was mentioned to be the final stage of a long descent from normal social behavior, and I would expect, in the general case, that we'd see very strange behavior that switches to be considerably more normal in settings where consequences might emerge. The tight-knit Orthodox Jewish community OP discusses likely had less severe and immediate consequences for weird behavior out in the open than you'd usually see, since everyone knew each other and there was less inclination to involve the authorities when a strange woman started pushing somebody else's stroller.
I was thinking more along the lines of someone who is socially aware and consequence-averse enough to put on a facade of normalcy when people are looking, but otherwise exhibits the same impulses (e.g. towards child abduction and other bizarre fixations).
Maxwell was not meant as an example of this, but as an alternate explanation for folkloric witches - someone who is sane but too evil to explain using an ordinary person's model of human behavior.
My aunt's family are ultra orthodox Jews, and I used to stay with them occasionally in Bayit Vegan for Shabbat.
Once I went for a walk with my cousins. Families there sometimes have dozens of children squashed into tiny apartments, and with the streets closed for Shabbat, the road becomes their playground. Hundreds of children thronging everywhere, zooming down the hill on tricycles, skipping rope or playing catch.
Suddenly we see an old unkempt woman screaming at the kids. Not that she's trying to sleep or to keep off her lawn, but that Hitler should have killed them all, and other similarly vile curses. The children mostly seemed to ignore her, but I was shocked!
My cousin explained: she was the wife of a Rabbi who had never had children. At some point she snapped and started to grab pushchairs off mothers in the street and happily push them along till the petrified mother grabbed it back off her.
Eventually she stopped even trying this and just used to spend her hours screaming and cursing the neighbourhood children. By now the kids were so used to it they faded into the background.
The cultural milieu in Bayit Vegan is probably not so different from a medieval village culture in terms of gender roles and the strong pressure to have large families. It seems likely that mentally ill infertile women in such villages would have manifested their illness in a similar manner.
In today's enlightened age we recognise such people as mentally ill. But imagine yourself as a villager in a medieval village, and you hear about an old woman snatching babies off their mothers and cursing children. The natural term that comes to mind is a witch, and the natural thing to do when a child goes missing is to search their property and burn them at the stake. Indeed, many times you might find the missing child in the witches house, further confirming your beliefs she was a witch.
I doubt this is the whole story, but this fits well enough that I think there is a very strong chance that this is a large part of the origin of the memetic complex of medieval witches.