Following an argument

I am beginning to seriously wonder if the Internet Age is rendering the modern brain incapable of the disciplined thought necessary to hold a principled position.  I have a lot of trouble believing that something like the Federalist Papers could be written by anyone in this current generation  much less expected to be read by any literate person in this modern age.  And comprehension being even less likely.

The most depressing aspect of this came to me last week when I should have been paying attention in my training class.  I was in an argument of sorts with a pro-abortion advocate who was attempting to justify abortion via an appeal to bodily integrity of the mother.  In short, the mother has the right to murder the child because in all other cases we do not force the mother to say, donate a kidney, if capable.  So why should she be held to risking her bodily integrity if she becomes pregnant?

Aside from the obvious point of when the mother engages in sex she is basically inviting the child into her body (regardless of steps taken to prevent conception) I pointed out that nowhere in law or custom do we accept the murder of the innocent as a means to any end.  He countered:

Him: A baby can be cared for by another, if the mother chooses to give it up, which she can. The fetus can only survive with the mother.
Me: Those two situations are not analogous, as the mother doesn't have to murder the child.
Him: No, but that is only because she doesn't have to.

Facepalm.  The whole point of the analogy was to show that the murder can be justified by reference to the idea that the mother can give up her maternal responsibilities by putting the child up for adoption.  The analogy fails because in abortion the child is murdered, which is clearly not the case in adoption.

The point of the contention was not that under certain circumstances the mother can give up her maternal responsibilities.  The contention was that this ability extends into murdering the child as a means to relieve those responsibilities.  But my opponent became confused and started to argue the wrong principle.

Which leads me to my main problem.  It is one thing for people to disagree.  It is another that the disagreement stems from a misunderstanding.  But when people can't seem to follow their own reasoning, how can reason be used to argue for truth one way or another?  When a person can't seem to focus and loses sight of what they are defending, how can reason be used to argue against it?

Sigh.  It makes we wonder why I bother sometimes.  I'm all for argumentation.  I'm all for reasoned discussion.  I would like to be corrected (and have been in other places).  But when the person I'm talking to cannot seem to follow their point, much less mine, what use is reason?