Barrie PS is certainly not alone in ethical lapses at the senior level. I don't know if there is an easily definable root cause but, in my humble opinion only, there are a couple of themes that keep popping up when we read about incidents like these:
-Spouses/intimate partners working for the same service. The more senior the rank, the greater potential for shenanigans. There is a largely discredited concept of the 'Chinese Wall' meaning 'an insurmountable barrier to the passage of information or communication". It needs to exist under a different name.
- Mentorship. Mentorship is key element in leadership. As a leader, part of your job should be identifying and developing your replacement. Problems can arise; however, when it focuses on identifiable groups and is encouraged under the guise of equity. Even without that, subordinate ranks who feel they have a pipeline to (or, as the article quoted, a "safe place") the boss is a failure of leadership. A TPS Superintendent recently got slapped for giving certain candidates a leg up on a promotional exam. If you haven't learned that by the time you make Inspector, you should make Inspector.
Former Chief Greenwood exercised her right to tell the investigators to pound sand; she's retired. It seems you can fail in leadership even when you are no longer a leader.