Regarding Cassell’s argument at the Volokh Conspiracy, Jody, I have no opinion on the merits of the particular case at issue, but generally speaking—in opposition to your claim—I think it makes a lot of sense to allow victims to present evidence at the sentencing hearings of offenders.
It makes sense not because we’re confusing torts and crimes—though violent crimes are torts, so I’m not sure that there is so much confusion after all—but because of the availability heuristic. As Tversky and Kahneman showed in work that later got a Nobel Prize in economics, people tend to systematically confuse the ease with which they bring a kind of event to mind with the objective frequency of that event. Thus, since we hear about horrific child abductions quite frequently but drownings in swimming pools less often, people tend to think the former are a more serious threat to children than the latter. The reverse is actually the truth by multiple orders of magnitude.
In sentencing criminals, the relevant considerations include not only the effect on the defendant sentenced but also the effects on his potential future victims if the defendant gets a light sentence. We cannot identify these people at the time the sentence is passed, however, and so they cannot appear in court. Because of the availability heuristic, there is a systematic danger that judges will overestimate the interests of the defendant whom they can see and underestimate the interests of the future victims whom they cannot see. Allowing the victims of the crime for which the defendant is being sentenced to testify is thus a rough corrective to this problem: it puts before the judge (makes “available” to him in the sense of availability at issue) the other interests he should consider and that he is otherwise likely to systematically underestimate.