Pre-womb and post-womb killing is still killing, motivated by the same over-arching agenda.
Pretty much every end of the political spectrum is aligned in principle with this by the way. The right claims to defend the unborn because families are scared of their babies being screened out, the left claims to stand for social justice and welfare to keep the screened half-alive, but both positions are easy to abandon for politicians. There are few of the common folk who will base their decisions on a single hot-button issue, and those groups are dwarfed by the highly vocal and highly influential eugenics movement.
Eugenics doesn't just mean killing the damned outright, either - eugenics is a tacit approval of harassment against the affected parties, who are deprived of even basic human liberties and dignity. The status of someone who is screened out is literally less than that of a slave, so much that everyone is DEATHLY terrified of the screen. No matter what happens though, the screen needs victims, and a whole lot of people will shove someone into the screen through deliberate terror to save themselves.
Eugenics is absolute terror and horror, the worst thing humanity has ever done and is still doing (more than ever).
edit: before this derails into abortion rights and nonsense about a woman's "right to choose" (a right which very quickly becomes social obligation due to eugenic principles, through soft and hard coercion, and in some cases compelled by state law - bear in mind that the old eugenics codes of the early 20th century were never repealed, merely re-written to remove loopholes) - before this derails, this really isn't about abortions being bad or good. I don't see any reason why abortions or infanticides need to be banned, if someone is willing to accept the gory implications of those acts (something which eugenists frequently do not, since it is not eugenist supporters being killed). It is more the reasoning behind those killings, and the ultimate motivation of the eugenist being glorification of their own authority. All of this is, ultimately, to reinforce the status of a few people at the top. There is no real dire necessity for eugenics or population control, given how wealth and resources are distributed and how operations are managed - the "crisis" isn't even manufactured, it flat-out doesn't exist.
