Dexter: Do we all have a Dark Passenger?

After recently doing much research academically on Dexter, I want to ask the question as a audience why we find it acceptable for Dexter to kill people who are ‘bad’. Dexter’s character has the desire to kill, his character has channelled these desires to only kill people who are ‘murderers’ he has to have evidence of this,but once he gets this evidence we as a audience want his character to kill them. Throughout the seasons, Dexter becomes our favourite serial killer.

Many academic texts argue the Dexter is the Post 9/11 serial killer, as a audience we want Dexter to kill the bad guys, for us terrorist are murderers who deserve death, therefore do we now have this notion for all other killers too?