Unfortunately, your belief that people should not force their religious beliefs on people is also, ultimately, a religious belief. And in fact, it's a religious belief that you are technically violating yourself by trying to force it on those Christians - which means you're ultimately taking up a hypocritical position.

I, personally, am an atheist / agnostic, who believes that a woman should have the right to choose. And I think most of your other arguments make sense.

But I really think there is very little ground to be gained with the argument that Christians shouldn't enforce their beliefs on others. Because ultimately, what you're doing is turning it into a matter of your religion against theirs: They believe, religiously, that they should enforce their values on others, and you believe, religiously, that they shouldn't. But both are religious beliefs. And there's no particular reason why your belief should take precedence.

The only way to actually win the debate is if you can convince them that their religious beliefs don't make sense, or are inconsistent with other values that they hold even more dear.

Does that make sense?