Neither bestial nor demonic, but rather savage, from the basic need to protect the vulnerable avenge the innocent.
Devising hellish methods of torture --- competing with each other to find THE most abominable method of torture --- has ZERO to do with protecting the vulnerable. In fact, it makes the torturers themselves vulnerable to obsessions, infestations and possession by the Evil One.
Torturers (and people who openly get off on sadistic boasting and torture-fantasy) are deforming their minds and instincts in a way that makes them more and more resemble the horror they think they are exterminating.
And "avenging"? This is forbidden by Jesus Christ.