I agree with everything you say and have also seen many poor supervisors! This person is obviously not a leader... A leader, whether it be situational, authoritative, etc... will know to never berate their personnel and will know how to handle situations privately. I'm a supervisor in law enforcement and volunteer EMS. It's a shame you've unfortunately had to experience a bad boss, but learn from their obvious mistakes and move on. As far as approaching them and their style: I would first see if there's someone in the agency they trust who might be able to speak with them privately, or if not, you'll have to do it on your own. You might be able to address the reasons why people are quitting in a monthly meeting or whenever your group gets together and see if someone addresses the problem in the open forum. Good luck!