You may feel sinning is bad but making it illegal to sin doesn't take away the choice, nor is it feasible.
there is 'sin' and then again there is sin.
"Sin" is about doing something one firmly believes is wrong. For instance, I believe that it is wrong for ME to drink coffee. Why?
Because I promised not to do so, and breaking promises is, well, wrong and a sin.
However, drinking coffee isn't a sin for you (probably) because you didn't promise.
To bring this closer to the mark, I think that sex outside the marriage bonds is sinning big time; pre-marital sex and adultery simply cause a whole bunch of problems and doesn't make anybody happy, really. Too much stress...and yes, I believe that both things are pretty big sins. However, I can't see making either one illegal; someone else might not see it as a sin, stupid as that may be.
See, that sort of sin only affects those who engage in it, really.
However, when one commits a sin that DOES affect others negatively, most people call those sorts of sins 'crimes.' You know, like stealing, assault, murder, fraud...stuff like that.
Abortion affects...actually ends...a human life. It ends a life that did not choose to be where it is, did not choose to exist and exits only (in most cases) because of the consensual acts of two people who honestly should have been more responsible. So, to get out of their responsibility to this human they created, they kill it.
Excuse me, but I find that to be....considerably more than just a sin that affects only the person doing the sinning and his/her own belief system/ethical system. THAT involves another human, who absolutely did NOT volunteer to be killed to ease someone else's inconvenience.
Ah, well....I think I have lectured on my soapbox sufficiently for the moment.