Earlier quoted context omitted.
Point is that second-wave feminism, and radical feminism in particular, centred on recognising sex as the basis of women's oppression under patriarchy. This led to advocacy for women-only spaces to protect against male violence and predation. Which is what JKR's position is: a continuation of second-wave radical feminism.
Partially correct but you are conflating the movement fighting for biological rights (eg: reproductive rights) as it being bio-essentialist. And there certainly was infighting about trans people within second-wave feminism (eg: feminist sex wars), but then there's also intersex people. Second-wave feminists more generally did not have the kind of one-drop rule towards womanhood as you do, where someone could have liv…
Also, you're responding to an argument I didn't make. I said nothing about intersex people or any "one-drop rule". My point was that second-wave radical feminism centred sex as the basis of women's oppression under patriarchy, leading to advocacy for women-only spaces. Which is exactly what JKR is defending.
That is the continuity I'm highlighting. It was in response to your earlier comment:
> Second-wave feminists would deplore her bio-essentialism. She is an anti-feminist.