Thanks for writing all that instead of me. I've heard the "we are not looking for someone to blame, just fix it" too many times. That sort of reasoning strikes me as protecting people's egos as if that's more important than not repeating the same thing over and over again. Both positions have merits, of course.
Because if we change nothing, it's going to happen again. That's how history got that reputation for repeating itself. But in order to prevent it, we need to understand the causual chain in order to break it.
For investigators whose work feeds into regulators it's a bit sadder because instead of "Why this won't happen again" the results are usually recommendations which, if followed, would prevent it happening again but you get used to them not being followed, so you're repeating yourself. "Why our previous advice would have prevented this from happening again".