[giucal]

Your own attitude towards life or criminals is not something worth considering when seriously pondering this question.

Society is a collection of individuals; everyone has different opinions and feelings on almost anything: at least when we discuss such sensible matters, we should rationalize our arguments, stripping any trace of subjectivity.

> I don't understand the great value placed on human life.

Coming to the case, you may not value your life very much, but we can't say the same for the criminal who is facing a death sentence. Personally, I don't feel empathy for some criminals who consciously perpetrated atrocious crimes; I literally fail to care for them. Nevertheless, I can objectively understand that in a civilized country any human must be granted some undeniable rights.

> I see no reason not to put down humans who have malfunctioned.

Humans do not malfunction. Humans err, whether deliberately or not. They must have the right to redeem themselves. And even if they refused to, putting them to death would still be a miserable solution: it wouldn't mitigate the crime, nor would provide justice -- and I mean justice, not revenge. Indeed, it would be itself a crime.

Edit: typos and form