Dealing with Duessa of "The Faerie Queene"

One of the most evil characters in the cantos that we've read in The Faerie Queen is Duessa, a woman whose name literally means "duplicity" and "falsity".  The amount of evil in which Duessa lives her everyday life appears to be more than that of other characters we've been introduced to; I think this has to do with the lengthened role of Duessa, where as other evil characters appear only for a short time in the text.  In every scene that Duessa is involved in the epic, she is doing something misleading, something that leads our protagonist closer and closer to danger.  It is because of this evidence of pure evil that I find it curious that when Duessa is captured by Arthur after defeating the giant, she is released with minimal harm and zero assurance that she will put an end to her evil ways.

In Stanza 49 Canto 8, the narrator tells the reader that "when they had the witch disrobed quight,/ And all her filthy feature open showne,/ They let her goe at will, and wander wayes unknowne" (7-9).  I don't understand why they would strip Duessa down to her bare nakedness and then allow her to escape.  I find the act of fully exposing her to be demeaning and revealing of her true character, but it is clear that Duessa is capable of recreating herself and committing all her crimes again to another unsuspecting individual; why would either of the knights give her another chance when they know just how evil she is?  In this bit of Canto 8, the evil is shamed but still released.  Why?

I've thought about this question and this particular scene for a while; many explanations have crossed my mind, but two stood out to me among the others.  The first is the idea that the good knights have forgiven Duessa for her sins, thus acting as a God-like figure (the biblical verse regarding the pure to cast the first stone comes to mind here), and the second possible explanation is that Duessa's release serves as a reminder to the reader that there will always be evil in the world, regardless of whether one evil individual is caught or not.  Both of these explanations require a biblical/religious reading of the text, but this is the most prominent reading for me; I find that both options illustrate a respective ideal that should be remembered by the reader.