There are so many people who want to hate Jack for being human. I'll bet a good many of these people who are quick to dis him are guilty of having the same negative qualities they accuse Jack of.

I believe part of the point in the show is to present multifaceted people. People who have qualities that allow them to shine, that would give you faith in humanity ... and other qualities that are not so commendable. Or pretty.

I think everyone in our lives has let us down and we have let others down in some way shape or form because none of us can live up to the standards people expect us to. To quote John Locke - "... it's what makes us distinctively human. "

They have tried, I think, to do the same thing with Ben, by giving us a glimpse into his own tragic history but it's difficult to have sympathy for a man who disregards the sanctity and dignity of human life and uses the the concept that it's for the greater good. This is a person who blatantly and with intent harms others for his own selfish cause. Unlike a person who has good intentions, who regards his fellow man with respect, but makes glaring and sometimes heartbreaking mistakes.

You can delve into Hitlers background and acknowledge his often painful and disheartening moments but it doesn't change the fact that he, being a man driven by his own satiable needs and thirst for domination managed to decieve literally an entire nation turning them into murderers and torturers, wiping out masses of another innocent and defenseless race.    

That is the difference between a person honestly struggling with doing the right thing, looking to find where he belongs in this world and a person who's embraced a truly evil lifestyle.