a war for kedushas yisrael

The Midrash comments on the pasuk וַיִּשְׁלַח אֹתָם מֹשֶׁה אֶלֶף לַמַּטֶּה לַצָּבָא אֹתָם וְאֶת פִּינְחָס בֶּן אֶלְעָזָר הַכֹּהֵן לַצָּבָא:

אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא לְמשֶׁה: נְקֹם נִקְמַת, אַתָּה בְּעַצְמְךָ, וְהוּא מְשַׁלֵּחַ אֶת אֲחֵרִים, אֶלָּא מִפְּנֵי שֶׁנִּתְגַּדֵּל בְּאֶרֶץ מִדְיָן אָמַר אֵינוֹ בְּדִין שֶׁאֲנִי מֵצֵר לְמִי שֶׁעָשָׂה בִּי טוֹבָה, הַמָּשָׁל אוֹמֵר בּוֹר שֶׁשָּׁתִיתָ מִמֶּנּוּ אַל תִּזְרֹק בּוֹ אֶבֶן. וְיֵשׁ אוֹמְרִים שֶׁאֵינָהּ זוֹ מִדְיָן שֶׁנִּתְגַּדֵּל בָּהּ משֶׁה, שֶׁזּוֹ בְּצַד מוֹאָב וְהִיא חֲרֵבָה עַד עַכְשָׁו, לָמָּה שָׁלַח פִּינְחָס, אָמַר, מִי שֶׁהִתְחִיל בְּמִצְוָה הוּא גוֹמֵר, הוּא הֵשִׁיב אֶת חֲמָתוֹ וְהִכָּה אֶת הַמִּדְיָנִית, הוּא יִגְמֹר מִצְוָתוֹ.

Why is there a hava amina that Moshe should have personally taken charge of the war against Midian? We don't find, for example, that Moshe was personally responsible to wage war against Amalek. At the end of Beshalach (17:9) the Torah tells us וַיֹּאמֶר מֹשֶׁה אֶל יְהוֹשֻׁעַ בְּחַר לָנוּ אֲנָשִׁים וְצֵא הִלָּחֵם בַּעֲמָלֵק and Moshe is not criticized for appointing Yehoshua. Why is the battle against Midian different?

When the officers returned from battle, they brought כְלִי זָהָב אֶצְעָדָה וְצָמִיד טַבַּעַת עָגִיל וְכוּמָז as a gift to the mishkan as a kaparah. Targum Yonasan writes:

ובכל דא חס לן למיתלי עינינן ולא אסתכלנן בחדא מנהן דלא למתחייבא בחדא מנהין ולא נמות במיתותא דמייתין בה רשיעיא לעלמא דאתי

The soldiers did not even look at the women of Midian. Considering that yefat to'ar is permissible at time of war, this would seem to be a very stringent and unnecessary chumra. Why was such a standard imposed here? (See Tos Shabbos 65 and this post.)

This past week the Torah world lost R' Avraham Yitzchak Kilav, a dayan, R"Y in Merkaz haRav, and a rosh Kollel. He discusses these questions and explains that the fight against Midian was not a battle over territory, a battle of conquest or in defense of Eretz Yisrael. The battle against Midian was a battle for kedushas Yisrael. The Midrash says:

אָמַר משֶׁה רִבּוֹן הָעוֹלָמִים, אִם הָיִינוּ עֲרֵלִים, אוֹ עוֹבְדֵי עֲבוֹדַת כּוֹכָבִים, אוֹ כּוֹפְרֵי מִצְווֹת, לֹא הָיוּ שׂוֹנְאִין אוֹתָנוּ וְאֵינָן רוֹדְפִין אַחֲרֵינוּ אֶלָּא בִּשְׁבִיל תּוֹרָה וּמִצְווֹת שֶׁנָּתַתָּ לָנוּ, הִלְכָּךְ הַנְּקָמָה שֶׁלְּךָ לָתֵת נִקְמַת ה׳ בְּמִדְיָן.

Midian's weapons, so to speak, were giluy arayos and avodah zarah. Their goal was to rip down the seyagim that protect our identity.  Therefore, when it came to this wa,r the normal rules of milchama did not apply. There was no heter of yefat to'ar because the whole point of this battle was to fight against the exposure to arayos that Midian used to undermine us. In this war sheivet Levi had to go out to battle as well, and the soldiers chosen were אנשים – צדיקים (Rashi 31:3), because these are the people who represent and preserve the kedusha of Klal Yisrael. And finally, Moshe himself should have been personally involved in the battle here. Rashi comments on the use of זה הדבר in the parsha of nedarim at the start of our sedra:

– משה נתנבא בכה אמר ה׳ כחצות הלילה וגו׳ (שמות י״א:ד׳), והנביאים נתנבאו בכה אמר, מוסף עליהם משה שנתנבא בלשון זה הדבר.

The neviim see the mitzvos that we have as they are, but Moshe sees beyond that and can grasp the parsha of nedarim, the ability of a person to prohibit that which is otherwise permissible in order to extend seyagim and thereby add kedusha. Midiam sought to undo the boundaries between Klal Yisrael and the outside world, so it is only fitting that Moshe, who was able to perceive that sometimes there is a need to even add boundaries, should be the one to personally deal with them.