"To you it's obvious that a late-term fetus and a newborn baby are identical. Yet this idea isn't accepted widely."

I don't know that.  In fact, I think most people who think about it believe there's no relevant difference between those little creatures.  I may be wrong, but I think many people who very strenuously defend Roe v. Wade would also defend the right of the state to step in at the last stages of pregnancy, because they see the equivalency and reject infanticide.  

Your question as to why there were 50 million abortions last year is well put.  I don't know the answer, but that number is staggering.  50 million lives gone at the hands of their mothers.  It's unnatural.

Finally, I agree that "I should think . . . more about why women get abortions in order to figure out how to save human lives."  I'll do that, and thank you for the suggestion.  But this doesn't mean abandoning an appeal to reason.  That would be very condescending.  

Again, thanks for the suggestion.