Exactly. In this article I was focused on regrettable turnover (when you wish the employee didn't leave), as opposed to non-regrettable turnover, which is very healthy.
In my experience, almost every time someone leaves someone regrets it and someone doesn't. The manager who supervised the person will usually say it is for the best. I have worked with great managers who clean house and terrible managers who drive people away, or treat them as scapegoats. In either case it may be identified as healthy turnover.