YOU SAID:
He never understood why what, when, and where left out who.
INTO JAPANESE
彼は、なぜ、いつ、どこで、誰を除外したのかを理解していませんでした。
BACK INTO ENGLISH
He didn't understand why, when, where, and who he excluded.
INTO JAPANESE
彼は、なぜ、いつ、どこで、誰を除外したのか理解していませんでした。
BACK INTO ENGLISH
He didn't understand why, when, where, and who he excluded.
That didn't even make that much sense in English.