ok let me clarify -
my PERSONAL stance on the subject is that nothing on this green earth justifies killing, not even when it's state sanctioned. There is more than sufficient evidence that murder as a deterrent for crime does not work, and remove that very dubious justification (even if it did work) you are left with killing for revenge in the name of the law. (Yes I feel strongly about this and no I don't mince my words). In addition the extremely negative psychological effects on those elected by the state to murder for them are also well documented (and yes the executioners do not justify it to themselves for long - they suffer incredible levels of depression, guilt and remorse.)
On any level I have never subscribed to the type of discipline that metes out as punishment the very thing you are trying to prevent some one from doing - at the very most basic level its like hitting Little Johnny because he hit Little Jimmy - 'Don't hit' SLAP ... VERY logical? - not! And if the law is not simply codified vengeance and it doesn't work to deter / prevent a crime then its ineffective and needs to change. Actually the statistics show that violent crime goes up in places where there is the death penalty. In some strange way the fact that the state kills makes it ok for every one else to up their levels of violence. And why not? If the leadership fails to respect the sanctity of life why should any one else?
However, coming from a country that has very high levels of crime and high levels of reprehensible crime (rapes, child rapes, molestation, etc) and where the death penalty was done away with fairly recently the subject of suitable punishment for certain crimes comes up fairly often. The general feeling, when people are outraged over a crime, is that for some crimes a quick death is too good for certain criminals - castration, slow roasting, torture all come up as good alternatives. Mostly the conversation goes 'if it was my child, wife, mother, sister, cousin nothing would stop me from .... insert slow death of choice'. It is a personalised highly charged emotional response to a horrible crime. So from that perspective the author was very clever setting up the first murder we see Dexter committing as being a murdering paedophile. On an emotive level most people would cheer Dexter on and ignore the clear wrongness of him, his thinking and his actions.
He is deliberately using a situation that, in most people, elicits a strong personal vengeful response to make an unsympathetic and unlikeable character both sympathetic and likeable (in a way).
I just don't find sympathy for any of them, yet. I certainly don't empathize.