Certain toxic people have the skill of destroying relationships or using powerful people or a network of people to exact vengeance on someone, and then pretending that they are innocent. The pretence of innocence can be accompanied by some cleverly dramatized sorrow or crying or white-lies. The deed done by the person can be purely out of jealously, hatred or misunderstanding.
Certain people are prone to sympathizing with such toxic people. Even if they are factually aware of the destruction the toxic person has caused, and they are aware of the reason. These people not only ignore the deed, but also support and protect the toxic person from others. What's worse, they support the toxic person even if the toxic person ruined the supporter's own life or relationship, or even if the toxic person backstabs them.
Is there a word or phrase to describe such people (or the behaviour of such people)?