There was a movie with John Wayne throwing a kid in that claimed he couldn't swim that did get a lot of play. Men worshipped them some John Wayne.
I have seen it done to kids and they would come up and they did tread water enough to make it to the edge of pool as they would not be thrown way out there. Some needed a little help to make it but usually just a pole or hand out was enough. I can't say they learned to swim but they did learn how to not die and it was the beginning of them learning to swim.
Hell, My Uncle would do it to every kid near the pool whether they were his or not and whether they could swim or not. He never killed a kid, but dang there were times I thought I was drowning and I knew how to swim but he would hold you down if you fought him and I did fight... well I struggled.
My oldest daughter took a swimming class when she was 3 or 4 with this older lady who was very intense. She yelled at screamed at these kids all week. After a week my daughter was fearless in the water and could swim the whole pool no problem. She is still a great swimmer and very comfortable in water.
A couple of years later my second daughter took the same class. She had been in pools with floats her whole life. After a week being screamed at and pushed in the pool she became petrified of water even the bathtub. It took me a year to get her back in the pool and she still isn't very comfortable on the lake 5 years later.