So effectively yes, this is already the state of things, and there is no serious movement to restrict this form of post-birth abortion. Who would have imagined that all it would take for abortion to gain acceptance is to frame it as a religious liberty?
(correct answer: anyone who's lived in America)
That is false. Parents cannot legally deny their children life-saving treatment.
Also, I'm not sure where I am being hyperbolic. Peter Singer literally does advocate for the "right" to kill young children for a long time after their birth. So if you say that Peter Singer offers an "easy" moral approach to abortion, I have to ask whether you actually do agree with his logic and follow it to the same ultimate conclusions that he does.
Euthanasia is a much more complicated topic and I find it bewildering that we are focusing on this discussion on babies. I assume it's out of some notion of protecting the adorable innocence. I think it's important with these topics to try to keep emotions out of it because they just reflect biases we have built in due to evolution. Evolution of course is not your friend. Especially not after you've procreated.