So remember how the meme of Right wingers is "bible thumpers"? Well it actually matters in this case.
The issue is that one of the strongest arguments against abortion is so simple a 5 year old can probably grasp it, and for those who are religious, it's not fallacious, in fact it is logically valid and true.
The basic argument isn't difficult and isn't even really a religiously based argument:
1) Killing innocent human beings is wrong.
2) Fetuses are innocent human beings.
3) Killing fetuses is wrong.
C) Abortion is wrong.
Now, this is simple but there's a problem. 1 and 2 both use "innocent human being" but they use it in different senses. In 1, "innocent human being" means a walking talking moral agent capable of decisions innocent of crimes against others. Without this definition, 1 is not true all the time.
In 2, the meaning of "innocent" hasn't changed (it's hard to argue that clump of cells is anything but innocent), but "human being" now means "human" in a genetic sense as at conception, it's just dividing cells. This is equivocation and makes the argument fallacious as it's impossible to make the argument that little clump of cells is a moral agent.
Well, impossible in a moral context devoid of Souls.
And this is the crux of why the Right makes a big deal out of it.
For the "bible thumpers", Souls dictate that even that clump of cells is strictly speaking a moral agent as that Soul is what makes that clump of cells human. This is what "life starts at conception" means in a practical sense, and why the abortion debate won't ever die.
So what does that mean? Well it means that the argument they are typically making is logically valid and true...because they believe in souls. For those of us that don't and those who deal in strictly logically derived morals, it's fallacious, but that doesn't change that not everyone believes that, and that's why there's so much passion from the pro-life elements, after all, from their perspective pro choice is literally killing children whenever you do it.
If you want to see a pro-life argument not mentioned here which is far stronger in a non-religious context, look up "future like ours".
Hopefully that clears up the why a little. Sorry for the sperg, I find the ethics of abortion fascinating.
