What do transactivists want to achieve by not making a baby's sex at birth?
Well, for one, no one would notice a trend in the abortion of female babies, because it would just not turn up in the statistics!
Murder of female toddlers? No one notices! All isolated, indidual very tragic cases where some random madperson kills a child. We don't know why it happens and can do nothing against it!
Women being paid less than men? No statistics.
Women never getting anywhere in professional sports? No one knows! What a weird coincidence that those people with uteruses and ovaries never get a gold medal! But who cares? Separation between women's sports and men's sports is just about women wearing pink and men wearing blue, but of course all professional athlethes were born with a penis.
Male violence against women? No statistics. Anyone who commits a crime can identify as a bag full of cats, and that's that then, police will be looking for a bag full of cats that is "dressed as a man", or something.
It is the perfect way of invisibling the oppression of women, now that feminists managed to achieve a state where admitting to oppressing women isn't viewed as acceptable anymore.
Feminism will probably reestablish itself some five hundred years from now, and will have some nice new name that refers to female biology, and will start all over again at zero.
But until then, patriarchy will rule supreme. If we cannot name our oppression, how can we ever hope to fight it?