"Dissociative disorder" is not the same thing as "Dissociative Identity Disorder".
You can Google the definitions of these things but they has nothing to do with cognitive dissonance or typical cultist behavior.
Unless Hassan's using the common/dictionary definition of the word dissociation instead of the clinical definition/diagnostic criteria sense), then I completely disagree with him. And even if he is, that is not the same thing as DID.
Calling cultism medical disorders mucks up the issue. Once we can understand what it really is, we can reduce it, but calling it something else eliminates that possibility.
Cultism is not a disease. It's a lot of things, but it's not a medical condition.