I knew he would freak out over it.

Spanking children as punishment used to be a thing in German schools as well not too long ago. (Late 20th century)

This is very much an example of what happens when people from the west view something and judge it by standards of the culture in the west, and are sometimes unable to take a step back and look at it from the culture it came from. It is also a very obvious gag that I genuinely laughed at out loud when I first saw it, i mean the dude literally has 3 wives and his actions aren't remotely sexual from the moment we see him taking them away. But it's also because people here in the west tend to only see cartoons as a "children's" medium or at most a "teenager" medium, and anime is no exception, which is also not helped by the Western distribution companies who stupid enough to censor the title of this very arc from the Red Light District Arc to the Entertainment District Arc despite it being a historical location, which then makes anyone who is a more casual viewer of anime completely ignorant of where this is actually taking place and what is actually happening in the story and did happen in history.