The reason that abortion on demand, to term, for any reason or none is extreme, is that it is placing sole emphasis on the woman and none on the foetus. In the same way that pro-lifers place all the emphasis on the foetus rather than the woman.
It is a tricky balancing act, but if a 36 week gestation baby is viable, and there are no medical issues in either the mother or the foetus, then once viability is reached, then surely the foetus has to be considered in addition to the woman. It is no longer a "potential life", it is an actual life, that will most likely live if born, without requiring medical intervention to do so.
The first medical ethic is "do no harm". So to terminate a foetus at this point would be actively harming a viable life. I cannot see many medics being willing to do so for non medical reasons. It isn't about saving the mother's life, or being "kinder" to the foetus by ending a life which will be painful or medically difficult to live with. So how can the foetus be terminated when to do so would go against medical ethics?
In addition, at this point, the woman would have to birth the child anyway. So the termination isn't preventing her from having to do so.
I understand that women may find it hugely difficult to give up a child for adoption. But does this mean her feelings warrant the foetus being terminated at say 38 weeks instead? I don't think so.
One of the basic principles in our society is that we do not kill. To terminate a healthy 38 week old foetus in a healthy woman seems to cross this line. And the willingness to cross this line, and prioritise a woman's feelings over another's life, is what makes the position extreme. There is no other situation in society where we actively end a human life due to someone else's feelings. That is what abortion on demand, to term, for any non-medical reason, is advocating should be a woman's right.