I harbor no ill will towards my parents or grandparents and I guarantee you it taught me what was and was not acceptable behavior. And pretty much everybody I know went thru the same thing. I'm not trying to "justify" anything. It just is what it is.
My mother and father would have been imprisoned and my brother and I would have been in the system. Belts, electric cords, switches (tree branch), hands, even hangers. Unfortunately this was pretty common among my friends as well as the accompanying welts. Funny but time out was always after the whipping, never before.
I will say boys got it whereby the girls didn't so much back in the day. I know now that much of the punishment was abuse or worse when alcohol was involved. And yes parent's frustration (probably unrelated to the crime) always made it worse or longer. Some kids can push your buttons and if you are not in a good space, they become the target/outlet for your frustration.
I will say I don't think it was that effective other than making us change our strategy (i.e. trying better to not get caught).
Its certainly a new day and even I was much more softer in disciplining my kids (both girls). I would never use an object, but I never had a problem with my girls. I can't say how I would have disciplined a boy.
As for AP I can not pass judgement and since this is no longer acceptable, perhaps parental counseling, like discipline strategies, or understanding when to discipline (e.g. not when emotional) is the solution for him.