Here's why:
* Avenge means to inflict punishment in return for a wrong or injury. This inherently implies harm and retaliation.
* It refers to an offense, wrong, or injury that needs to be avenged.
* Destructive because the act of avenging often involves inflicting harm or causing pain, which is inherently destructive.
While the motivation behind seeking revenge might be rooted in a desire for justice, the act of avenging itself is typically considered a negative and destructive action.