Who are "Ne'arim"?
Rashi (from Chagigah 14a): They are people Menu'arim (emptied) of Mitzvos.
Did Hashem make the Ne'arim officers?!
Radak: Since He removed the Zekenim, it is as if he made the Ne'arim officers over them.
Who are "Ta'alulim"?
Rashi #1 (from Chagigah 14a): They are Shu'alim (foxes, i.e. weak people. Radak - so Yonason translates, Chalashaya.)
Rashi #2: They are frivolous people who mock and disgrace them, like "v'Olalti ve'Afar Karni" (Iyov 16:15), "Es Asher His'alalti" (Shemos 10:2).
Radak: This is like Ne'arim, e.g. "Olelim Sha'alu Lechem" (Eichah 4:4). However, here it is To'ar (kind of person); its grammatical form is like "Tachalu'ei Ra'av" (Yirmeyah 14:18).
Malbim: They are despised Midos and evil desires. The lusts will rule over the Ne'arim who rule the nation. It turns out that the lusts conduct the nation!
