"Thine eye shall not pity her"

In a previous post I mentioned that the Quran (5:38) requires the amputation of a thief's hands. Many Christians, no doubt, would consider such a punishment cruel, yet the Bible requires the very same punishment for much different crime.

What crime would be punished so severely, you ask? Well, I'll let the Good Book tell you directly:

When men strive together one with another, and the wife of the one draweth near for to deliver her husband out of the hand of him that smiteth him, and putteth forth her hand, and taketh him by the secrets: Then thou shalt cut off her hand, thine eye shall not pity her. -- Deuteronomy 25:11-12

So the Bible says that in certain circumstances we must cut off a woman's hand, and we must do so without pity.

There are some Christians who believe that the Bible's laws (including the one above) should be enforced today just like they were in the time of Moses. I suspect, however, that most Bible-believers would disagree.

I'd like to understand the reasoning of believers who would refuse to follow God's law -- that is, who would refuse to cut off a woman's hand without pity as commanded in the verses quoted above.

Would it be right or wrong to enforce the law today (assuming a woman was guilty of the "crime" described above)?

Would it have been right to cut off her hand a few thousand years ago but wrong today?