I was a bit confused too, but OPs answer to your comment clarified it quite well.

And after thinking a bit on it, and from my very basic knowledge of lgbt movment, here’s what i think they advocate for (pls correct me if i say bs) : sex and gender are indeed different, they aee not necessarily connected and both are spectrums rather than binary options. This means you could have a lot of options between what sex you are (male/female/intersex), what gender you are (a lot of options) and what gender you were assigned at birth (generally either male or female). Some trans people need their “physical” sex identity to match their gender, other don’t.

The problem in this case seems to me that she advocates for a strict binary conception of sex identity and that she pushed for it to be more important than gender in social situations such as sport. Part of the confusion also comes from the fact that she acknowledges parts of what the lgbt movment fights for but she fights against the rest, which happens frequently in TERF rethorics afaik