It's not worth getting in a bother about, People have just latched onto this name, because it must have started somewhere, with some Karen being a bit dumb and idle, well that's how I thought it started off..
I only know two Karens, One of them was a top class hairdresser, with her own salon, and very hard working with a flourishing business.
The other one I didn't know, but heard someone calling her that name, when I was sitting on a small wall outside a Primark a few years ago. She was very very overweight, dressed in Pyjamas in the afternoon, sitting on the wall , eating two huge burgers, and some cans of fizzy drinks., she was often swearing at her two kids, running about all over the place, and belching loudly after drinking the fizzy drinks.
But I don't associate the name Karen, with anyone with that name;, its a bit pointless to be thinking this way.