I was teaching at Cronulla High School from 1966 to 1969 and have to say I never heard anything quite like this harangue which occurred at another place in the same period.
I have heard one or two almost like that, but really that is one of the most sustained moans I have ever heard. I wonder if it was effective?
Hat tip to Pip Wilson who featured the vid recently. It’s his old school!
Back to Cronulla when I lived and worked there. I guess people did look like this: