Making Calligula watch while Rome burned and all of his favorite minions were killed would be evil.
Actually, I think the whole "burning Rome where all these innocent bystanders live, work, and raise their children," would be the evil part, not making Calligula watch.
Making Calligula watch would be rather ineffectual for the reason you already noted.
Doing to something that is ALSO evil doesn't mitigate that fact. Cosmic Evil like D&D Evil isn't just "evil under certain conditions." It is what it is -- it likes it when you try to make things suffer. It doesn't really care WHAT you make suffer. Clearly, V is trying to make the dragon-momma suffer.
Um ... not really. The idea that Suffering == Bad or that causing someone else's suffering is automatically evil is rather unfounded.
Heck, putting someone through the DTs is some of the most painful suffering you can inflict on another human being. Relieving that suffering by feeding their addiction, however, is immoral.
Suffering isn't morally charged.
Why suffering is caused gives the act its moral onus. Making someone suffer to make yourself feel better is typically textbook cliched villainy Evil.
Actually, no, a Just punishment is specifically designed to make sure the criminal does NOT suffer.
Um, that's your opinion, I suppose. D&D takes place in a setting where "Just punishment" for thievery and vandalism is typically corporal punishment - inflicted suffering to deter the offender from further transgression. Pain and loss are natural teaching tools that can help positively shape an animal's behavior (humans included) or they can be abused to negatively shape that behavior.
I mean, that's the philosophy behind jail and even execution. It's not there to make the people experiencing it suffer, it is there to isolate those who cannot function in society without being a risk to others (and to remove them when isolation isn't enough).
Actually, the philosophy of non-corporal punishments such as imprisonment and fines stems from the idea that hurting a man's livelihood and liberty is more effective way of getting what society wants than simply hurting his body.
- Marty Lund