I am totally perplexed as to why some people are arguing the toss over this. It is de facto a case of a pejorative term having a slight negative racial and sexist aspect.
It’s a relatively lightweight example yes, and not of the same type as some others (does not apply to all white women for example, and existed before its most recent incarnation) but that’s hardly the initial point, which is that it is used as a pejorative term with a negative racial and sexist component.
After that, it can be said that it’s not that serious an issue really, compared to many others.
I think it's critical to distinguish a pejorative term that is applied base upon individual behaviours that are correlated with race versus a racist pejorative that assumes behavior based on race.
Calling a person a white supremacist is pejorative and is applied exclusively to whites, but if it's based upon an individual actually behaving in ways that reveal white supremacist ideology is it racist to call someone that?
There is that distinction, yes. In some ways at least, though not entirely, it's a bit like Shylock, where a Jew usually has to be seen to behave badly (be money-grabbing) before the term is applied (though it can bleed over into an assumption that most or all of the target group are at least somewhat Shylocks, even if money-matters only get mentioned by them, which may happen with middle-class, middle-aged white women who complain, and I think has, to some extent). That said, I don't feel comfortable saying there isn't still at least a small, perhaps insidious racial and sexist component to, well not just the word (Karen), but the fact that its use has spread like a (small) wildfire on the internet and into common everyday language. It's a bit like the word bitch, except (a) it's a woman's name in this case (which is a bit of a pity for women called Karen, especially if they are middle class, middle-aged and white) and (b) bitch is used for all races.
I would ask whether the word bitch is in fact used in situations where a woman is merely being assertive, in a way that would not be (as readily) considered worthy of a pejorative for a man; that there is a perceived lower threshold for female behaviour in other words. The Karen in one of the videos above, for example, was objecting to what looked like about 20-30
'awesomely noisy' (male commentators words, if I recall correctly) souped-up cars being driven through and revved up in what looked like the otherwise quiet residential street that she lived on. To me that's not an unreasonable complaint, and even peaceably standing in the road to try to stop them doing it does not seem an entirely unreasonable piece of direct action (she didn't, as far as I could see 'lose it') although a different mode of complaint might have been better (but possibly nothing would have been done).
What's next, middle-aged women at board meetings feeling they can't strongly disagree with something in case they are afterwards labelled a Karen?
So I'm thinking that if you are a middle-class, middle-aged white woman and you complain about something, you are in danger of becoming a Karen almost by default.
All that said, I'm not losing any sleep over this. It obviously pales into relatively trivial insignificance compared to many other issues. But then it's not aimed at me because I'm not a middle-class, middle-aged white woman. And I know that the term Karen (a bit like bitch) is sometimes used for men, and indeed black men, but mostly not, and there is the male equivalent of Karen (Ken, or is it Kevin) but again that doesn't seem to be cited nearly as often. I admit I haven't seen many male anti-mask protesters labelled a Karen (or even a Kevin), although I guess there may be examples. In fact anti-mask pejorative terms other than 'anti-masker' seem to have mostly become associated with women, even though there seem to be about as many male anti-maskers (I haven't done a survey). So is it the case that humans behaving badly attract popular pejorative terms more readily when it's women doing the same behaving?
I also don't tend to buy the claim that something isn't racist or sexist just because it's aimed at someone in a generally dominant or privileged group. It's still what it is, imo, although it can be said that its effects are usually much less severe, and so two otherwise like-for-like cases of it arguably shouldn't be put on a par.
