You don't have to be religious to appreciate the arguments against abortion. Freely killing your offspring has already had devastating effects on a number of social issues.
Just goes to show how shallow left thinking really is.
Actually, you do have to be religious, and have some specific beliefs, to appreciate some arguments. Well thats not true either. You can appreciate that the argument "my religion says that conception/implantation is the significant beginning of life" affects some people's thinking. If that point is taken, if the zygote is a fully valued and independent life at that point, then all abortion is murder. If a person does not have this belief they may or may not be able to appreciate the believer's perspective but they almost definitely won't hold it themselves.
There are, of cause, other arguments against abortion, but all too often the statement "Abortion is murder" is presented as a fait accompli. If the anti-abortion position is argued this poorly, not only can it fail to have the slightest ability in convincing a non believer, but it can convince them that the anti abortion basis is entirely religious with some extra arguments tacked in an attempt to get up the numbers.