I wonder the same thing. If it is not a person, then watching this would be no different than watching a program on open heart surgery, liver transplant, or an appendectomy. There are certainly lots of documentaries which show various surgeries on humans. What is the difference to a pro-choice person?
I also wonder at all of the PSAs, brochures, pamphlets, books, videos, etc., about what women should NOT do, while pregnant. It seems to me that, if a fetus is not a living human being, a pregnant woman should be able to do all of the drinking, drugging, smoking, etc. that she wishes.