I make mistakes all the time as a developer, I would hate to be fired for them and if I would, I would never claim responsibility.

And that's why I don't get how people expect directors/managers to be infallible.

Taking responsibility isn't about walking away from the job, but learning from it and making it right.

Whether that is done well in this case, I don't know, but that wasn't your point. As far as I can tell they got pretty decent severance packages.