The first, abortionist David Baram, entirely fails to engage the crux of the matter -- the moral status of the being who is killed by abortion. He relies on storytelling and question-begging rhetoric that does nothing to actually establish his position or refute that of his opponent. Pro-choice activists in the audience seem somewhat pleased, however, because his rhetoric matches their own (and that of NARAL, Planned Parenthood, et al.).
The second, philosophy professor Mark Mercer, concedes the biological fact that the unborn is a living member of our species -- a human being -- and that abortion is the killing of that young human. He correctly dismisses the fallacious pro-choice rhetoric (about "choice," etc.) Baram and others use. This alienates his supporters in the audience. Mercer instead offers a serious argument for the permissibility of abortion, proposing criteria for "personhood" and concluding that human beings do not acquire full moral worth until about 18 months after birth.
The pro-choice reaction to Mercer is revealing:
"You didn't even attempt to make any arguments that would convince anybody of anything," said one activist. "You did not represent the pro-choice position at all."But Mercer, unlike Baram, offered a legitimate argument for the pro-choice view. Mercer, unlike Baram, was thoughtful (and I respect him for it).
The differing crowd reactions reflect, I think, the intellectual state of the pro-choice movement, its aversion to thinking clearly about the abortion issue (see Schultz, David), and of course the horror of conceding the logical implications (e.g., infanticide) of the pro-choice position's denial of fundamental human equality.