They're erasing the category of sex. That leaves female people without a recognised, defined category, which is essential to mount any sort of defence against sexism - in a world that remains acutely aware of which sex is which, when oppressing the female half. Nobody cares about gender identity when sex-selective abortion, or genital mutilation, or child marriage and other forms of rape are at issue. Nobody is confused when seeking a surrogate.
It's straightfowardly abusive and oppressive to erase sex, most especially when discussing reproductive and sexual vulnerabilities and harms. They underpin women's subjugation throuighout the world, and by erasing them, you remove women's capacity to defend themselves against that subjugation.
It bemuses me, that people who earnestly believe themselves to be human rights activist can collude in this destruction of one of women's most basic and fundamental right - the right to exist as a collective legal entity at all.