"Don't get mad, get even." ~Robert F. Kennedy
To add more onto this, revenge being a gray area, never black and white, some of the greatest stories ever told had to do with revenge. The Count is a good book because it did show revenge wasn't perfect. But it still showed the human nature and portrayed honestly, the nature of revenge. It is a process in itself.
Even in the scriptures, esp. the old testament, the Abrahamic God was huge on revenge over enemies.
So in truth its a gray issue. And as far as offering release - it can be the end point for another. And may teach another individual, better off not creating enemies in life, in the first place. Sometimes revenge can, be the getting 'even' that another needs. Just another version of karma.
In all cases, no. Well thought out and plotted, why not?
Confucius probably said that because many women wanted to get revenge on him for his oppressive ways. That's all.