In total fairness, King of the Hill specifically pertains to a lot of American culture. Japanese media will of course contain Japanese things, but the entire joke of King of the Hill is that it's the average lives of a bunch of average Texans.

It would be like watching a Japanese historical drama in Japanese vs English, it adds something to the flavor.

Japan's always sort of liked the English language though, so it's not that big of a surprise.

It's why so much stuff like anime and music will randomly have English thrown in.