Let's parse it, shall we?
I think the "defect" of those with multiple personality disorder is that what happens to them is this approach breaks down and they tend to get "stuck" in one personality for much longer than "normal" people do. So, their problem is not that they have more personalities than average, but that they spend much too long in any one mask, where as the average person applies many personas to the puzzle.
"Defect" - not language I would choose. I've seen people turned into vegetables or die because they couldn't dissociate adequately enough.
"Not that they have more personalities than average" - All alters are fragmented parts of a whole, they aren't additions in the sense of how they are created, but once created, because of their relative independence, their skills, opinions, feelings, etc. are often developed to a greater degree than a "persona" in someone who doesn't have DID, and sometimes they develop extraordinary abilities.
"This approach breaks down.....stuck in one part" - assumes that only one alter is currently or consistently "out". This is false. Assumes that alters not currently "out" do not react to current scenarios. They often do. Their reactions may be more varied and therefore internally inconsistent to the whole, and some individual reactions may even be unhealthy, but this isn't always a weakness. There's that old adage,
sometimes two heads are better than one. Example: I have an internal republican who helps me hone my arguments in political discussions.
Review this list of ten benefits of having DID:
http://rigorousintuition.ca/board2/viewtopic.php?p=488803#p488803Being able to do more than one thing at the same time.
Always having someone to talk to.
Being able to maintain the joy of a child's perspective.
Being able to take a break even when the outside body has to keep going.
Having the ability to remember so much more of life's experiences.
Having the ability to understand life and events from a variety of different perspectives.
Blocking out pain.
Quite possibly needing less sleep?
Looking younger.
The ability to fit in with a variety of different people.
I could flip all of those on their head and proclaim them comparative defects in so-called normals.
What is your point in hammering on the perceived inadequacies of people with DID if not to castigate us for fucking up the world because we cannot address problems in a more integrated manner? What is the point of telling women we're fucking up the world by inadequately addressing patriarchy? Why are you singling out the "other" for your castigation?
Why can't a man who wants to understand women respectfully inquire, read, and then listen? Why can't people who are interested in DID respectfully inquire, read, and then listen? Why must an insulting proclamation be made which sets the other party on the defensive from the very beginning? I've responded far more than I ever intended to any of these discourses, which are abusive in nature.