that's for the people who are still alive, stop resisting the information you are given!
not everything has to work with what you perceive wow (and world!) to be.
have you ever been so tired of things around you that you just want to sleep and have a moment of piece by not being conscious and dont remember your problems? maybe not, but a lot of people do, so its understandable that those noble souls who happen to share a lot of good traits, may want to just forget everything, after all it doesn't matter anymore, what does it matter who helped you or wronged you when its all finished and done?
AND their job is to, as of course many other players pointed out, is to fetch dying souls and deliver it to arbiter so she can decided which covenant suits the soul best.
THE KEY POINT here for you to understand so you can understand the whole picture is the arbitar is the best possible entity to judge the souls, you cant get better than that even if we find out that she is not perfect, she is the closest thing to perfect.