It would be best to accept that English education here is not intended as an actual foreign language cirriculum[sic], but as a sorting method, and highlighter. As a sorting method, English is ideally suited because it is a highly complex system with a lot of idiosyncracies. By placing it on entrance exams, you can generally sort the good students from the bad by their English skill (the general thinking being that if you can master the complexities of English, then you can master anything else - the SAT and ACT is guilty of this same thing, only they test you on how many ten-dollar words you know). As a highlighter, English serves as a backdrop from which Japanese and Japaneseness are contrasted, thereby helping to instill nationalism in the students. Similar results are achieved through "Internationalization".
English education here would be radically different if they actually intended for these kids to learn the language, as opposed to mastering a complex system.
They could save a lot of money by inventing a complex cypher and having the kids learn that, instead of paying ALTs to come to Japan and suffer through watching their language gang-raped repeatedly day after day.