People
Revenge is the naked idol of the worship of a semi-barbarous age.
— Percy Bysshe Shelley · A Defence of Poetry

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker describes revenge as an idol worshipped by a partly barbarous age. The image turns vengeance into an object of devotion rather than a reasonable response. Calling the idol naked strips away any dignity its worshippers might try to give it.
Context reviewed