Because I have yet to encounter a staunch opponent of abortion who doesn't drag religion into it sooner or later. If you look at the big picture, and look at the cost of abortion vs the personal and societal costs of women having children that they aren't able or willing to take care of, abortion wins. That's why it is legal to one degree or another in virtually every industrialized "first world" country.
Actually, no. When the doubters say, universal health care would costs $X, and the numbers that most on the right are talking about are pretty shaky, it makes it sound like we - the government and people with their own healthcare plans - are paying nothing. When you take all those costs, and add in how much health care providers lose every year when people show up at an ER where they have to be treated, but then can't pay the bill, universal health care looks like a better deal, because people would have access to preventative care so they wouldn't need to go to the ER.