I agree, and I also agree that Darlie has not lived up to Karla's in-prison example. It is just that Karla is the only example I could come up with that people might not want to see executed, in spite of the horrific crime. I do not think anything was served by killing her either.
There are times, however, when executing someone does serve society. Who should be the judge of whom to spare though is an even bigger question. I suppose the powers that be wouldn't want to broach that subject, and I can't blame them. Most of us would never agree and we'd still be hollering for change.
I know that Darlie and women like her do not deserve mercy on the basis of their crime, but on the other hand, it is such a shame to see life like that wasted, esp when the Karla H's are footloose and fancy free in just a few years.