Could it be that because your "alters" are somewhat indendent of you, you can distance yourself enough from them to be more accepting of their faults and more acknowledging af their gifts? When I get depressed I assume I can hate myself because I "know myself" so well, when actually my mind is blocked from seeing the positive in myself. If you don't have that much access to the alters' experiences, it's easier to be forgiving (You don't "really know" why they feel as they do) and easier to see their good points as an intregral part of them.
Are they you? Oh yeah, and you are them and you all developed to help each other survive. How do they feel about you?
I for one think that what you all have is a gift that very few others have, but I realize that you feel depressed partly, if not mainly, because of what made using this gift necessary. What ever this was, never let its echoes convince you that you should hate yourself, Elysium. is there something particular that bugs you? Or is it just a general feeling?