...is that first part supposed to be a serious argument? The other side would say the exact same thing. It's also an issue that inherently will never be black and white because children don't develop in discrete stages, you can never point to a specific time and say "until here it's ok". Some of the arguments for abortion even still apply post-birth, such as the parents not being capable of caring for the child properly, making everyone including the child miserable. And the child a day before birth isn't all that different from the child the day after.
I'd choose birth as the arbitrary cutoff point just because the child stops being part of the mother at that time and we have to put a limit somewhere, but I'd probably lose a lot of people with that (and I'd also still say that's the right thing).
When there exist people unironically making the argument that factory farming is good actually because any life is better than no life, of course there will be a lot more wanting to just defend life for the sake of it even if it just makes everyone involved more miserable.