Isn't any form of "monster" just a cheap "this thing is evil" marker?
At what point is something a monster that does bad versus a bad guy that does bad?
We don't hold a tiger morally responsible, while most of the beings on the tv show Supernatural would be, since they're capable of making moral choices. Even the ST Borg understand morality, although they consider it irrelevant. But the Federation would probably hold them responsible, if they had the power to put the Borg Queen on trial, like they ended up doing with the Changeling lead female character from the Dominion.
Tiger Tiger. burning bright,
In the forests of the night;
What immortal hand or eye.
Could frame thy fearful symmetry?
... fire of thine eyes ... dread hand... dread feet ... dread grasp ... deadly terrors, etc., etc.Blake.