@LysandersTreason
You have to remember that this incident is not in the manga because it's common or accepted but for a specific purpose, to let the readers know the origins of Hogorilla's trauma and to make the father and son look bad. So it's supposed to be upsetting and unusual. But I think the mangaka laid it out really well. If you read what the father is saying, he's choosing his words very well. He mentions his son's possible misdeed without admitting to it so that he can appear reasonable (because of course his son is a little shit and he did something wrong) and follows up with another very reasonable statement. Then he smoothly switches over to speculation and thinly veiled threat (about the story spreading and growing bigger). Lastly, he concludes very confidently and directly on how it should be resolved. And even though he's saying something that's unreasonable, he's built it up to that climax using reasonable steps and slowly escalates it until what is actually outrageous and insulting seems a proper and appropriate conclusion. So it's not like he just stormed in and said, "My son got hurt, fuck you, dogeza now!" Instead, he very smoothly led the talk until the conclusion reached what he wanted in the first place. That's politician for you.
Whether it happens in Japan is beside the point because it's being used to tell a story and provide a background.
@Purplelibraryguy
Our Hogorilla is actually 190cm (6' 2"). It's in one of the omake that I didn't translate. Pretty big dude, especially in Japan. He can jump up to his feet from a supine position so he's pretty athletic and strong too. Smashing a little high school dude like that would be no problem. Kosugi is about 5' 1".
https://imgur.com/a/i2yIPAv