Well, because our President is a hard core pro-abortion ideologue who has exhibited more hostility toward the unborn than almost any other elected official in America. This is a man who voted against a law that would mandate life-saving measures for infants that survive abortion, and who famously stated that he wouldn't want his daughters "punished" with a baby if one of them "made a mistake" and became pregnant out of wedlock.
With these new ads it's clear that Mr. Obama is doubling down on the leftist rhetoric, attempting to fire up his base by appealing to issues that garner the most impassioned, emotional responses. Since he cannot defend his record on jobs and has himself previously suggested that he should not be reelected if he fails to fix the economy in his first term, his only option at this point is to distract and obfuscate as much as possible. Hence his manufactured "war on women" - a tactic based upon the assumption that subsidized birth control and the legal ability to destroy their progeny at will are the single most important issues to American women.
It is a sad state of affairs when the best thing an incumbent President has to commend to the voting public is a reckless disregard for the sanctity of human life and the embrace of a court ruling that has sanctioned the destruction of 50 million unborn children in the last 40 years. What is equally sad, however, is that the Republican Party lacks the integrity and the courage to robustly defend their pro-life platform for fear of negative political consequences.
Right now it may seem like defeating President Obama in November is all that matters, but conservatives may find that the price of that victory comes at the cost of the Grand Old Party's soul.