Why is the Conservative Right so set against abortion?

I've never been able to figure out why the Conservative Right is so set against abortion. We're talking about a group that complains about the high birth rates of certain groups of people and then tries to limit an option that, by and large, only lowers the birthrates of these groups. That seems kind of self-defeating.

Plus there's the fact that it costs elections. There are plenty of middle of the road people that would accept Tea Party views of economic policy if they didn't feel they had to accept the Fundamentalist views on morality that go along with it. Tea Party people, I know you're about the economics, but until you realize that you've allowed people of Fundamentalist morality to become associated with you in the public mind and fix that, you're dead in the water.

Of course, abortion wouldn't be as much of an issue if the government would fully subsidize contraception. Imagine, contraception for free, on demand, and not just condoms, I'm talking everything, including surgeries. Yes, it costs money, but a lot less then welfare checks for the resultant children would and the cost of abortion clinics. Of course the Conservative Right wouldn't go for it. Only abstinence is viable. Isn't that pushing your morality on other people? Isn't that what they keep claiming the Progressives are doing?