An interesting rant as usual, but yeah - while the arguments in the book certainly remind one of the real abortion debate, it's not as if the book or Meyer really claims to have a meaningful input into that debate. In addition to the alien lifeform thing, the main reason why all of Bella's family, including the father of the "fetus", desperately want her to "abort" is because they are fairly sure giving birth will kill her. But she insists anyway, with the support of one of her "sisters-in-law", although you're right that those aren't actual family relationships, merely vampires banding together and acting like a family. And of course it doesn't actually kill her (although as I recall, the birth does in fact mortally wound her, what with her still being human and all that, and she survives only by immediately being turned into a vampire).
So it could be interpreted as an encouragement to give birth no matter what even if there is serious danger for your own life - if Bella does so with a fetus that's not even human, surely you can do it with a human fetus! - and in that sense it impacts the abortion debate. If you're the kind of person who would take messages from a dubiously written supernatural teenage romance, that is.