...about why the people you're assigned to kill during the Dark Brotherhood questline deserve to die? ....
Many of them don't deserve to die. Your character is in many cases killing innocent people to gather their souls for the Night Mother.
For example, Baenlin was an upright, respectable citizen of Bruma. Apparently his nephew wanted him kill to inherit the house.
Francois Motierre had Lucien kill his mother so as to get out of his gambling debts. The Dark Brotherhood was perfectly happy to him is mother for her soul, even though she did nothing wrong.
Even Adamus Phillida devoted his career to attempting to protect others from the Dark Brotherhood.
Not to mention the poor family in Next of Kin, or the party goers in Whodunnit.
If your character does the Dark Brotherhood quest he or she is murdering people who have done nothing wrong period.
And your friends are fine with that. And fine with killing a little girl at her 6 year birthday party.
...I remember reading somewhere about Rufio, ...
Rufio apparently killed someone (a female) close to Claudius Arcadia who is now imprisoned for apparently arranging the mission.
If questioned Rufio says:
"No! Please! I didn't mean to do it, you understand me? She struggled! I... I told her to just stay still, but she wouldn't listen! I had no choice!"
Some people think that implies attempted [jeepers the implied crime was auto censored, okay let me reprhrase doing something to an unwilling female], but it seems to me there are other possibilities, some not evil at all.
...
What if find ironic is that some of the same players who happily slaughter that innocent family of five, then cry about taking out their fellow psychopaths during the purification. :rofl:...
Another hand raised. Acadian knows how I feel about the DB.