You're crossing the streams, Jon. Let's start with your first premise, that we oppose birth control. We don't oppose birth control, and it seems clear that you are no longer actually arguing that we do. Here's a random bill by Republicans proposing to allow birth control to be sold over the counter, for instance. (opposed by Planned Parenthood, cause, you know, profit that they don't care about making).
http://thehill.com/policy/healthcar...icans-call-for-over-the-counter-birth-control
So now we've evolved to a more nuanced argument--we oppose the state paying for birth control. Generally speaking, probably true. Now, we can make policy arguments about that, and the tactic of pointing to abortions prevented is a good one. I might even be swayed by that in some instances. But let's not confuse the two arguments. Not want to pay for it and wanting to outlaw it are two very different things. For instance, I don't want to pay for abortions AND I want to outlaw them.