"As far as the principle goes, the bottom line is that the utter cruelty of totally and permanently ending the existence of someone without their consent is far greater than the utter cruelty of enduring an unwanted pregnancy and the mental trauma, and then giving the child up for adoption. I truly do not want to minimize that."
This is a false equivalence, the woman is an independent, autonomous person; the zygote is dependent, partially developed and not autonomous.
Your description of "permanently ending the existence of someone" is a romantic notion. I get where you're coming from, every zygote is unique and the person they would've developed into will never exist again
Every life that already exists outside a womb is unique and valuable, you cannot impose control and suffering on the bodies of strangers for your idealistic notions.
Adoption is not realistic; most children in the care system stay there, the older a child gets the less likely they will find permanent home.
The reality is that the majority of these kids are rejected, repeatedly rehomed and abused in one way or another.
Have you ever done any research into people's experiences of it?
Have you ever done anything to support it?
Do you regularly encourage people to adopt older kids?