difference between meat/wine and laundry/haircuts right after the fast

 The SA writes in 558:

 בְּתִשְׁעָה בְּאָב לְעֵת עֶרֶב הִצִּיתוּ אֵשׁ בַּהֵיכָל וְנִשְׂרַף עַד שְׁקִיעַת הַחַמָּה בְּיוֹם עֲשִׂירִי, וּמִפְּנֵי כָּךְ מִנְהָג כָּשֵׁר שֶׁלֹּא לֶאֱכֹל בָּשָׂר וְשֶׁלֹּא לִשְׁתּוֹת יַיִן בְּלֵיל עֲשִׂירִי וְיוֹם עֲשִׂירִי. {הַגָּה: וְיֵשׁ מַחְמִירִין עַד חֲצוֹת הַיּוֹם וְלֹא יוֹתֵר

 

The MB comments:

 

ה״ה שלא לרחוץ במרחץ ולספר ולכבס עד חצות

Yet if you look earlier in 551:4 it says you are allowed to do laundry and get a haircut right after the fast ends:

 

לְאַחַר הַתַּעֲנִית מֻתָּר לְסַפֵּר וּלְכַבֵּס מִיָּד.

 

The MB there comments on the spot:

 

עיין לקמן סימן תקנ״ח באחרונים דמצד מנהגא יש ליזהר בזה ביום עשירי עד חצות היום:

 

What he is saying is that the SA in 551 basically neglected to tell us about the minhag of waiting until chatzos that he will mention a few simanim later in 558, but read one in light of the other.

 

There is a simpler solution that reads the SA k'peshuto.  Meat, wine, laundry, and haircuts are not all the same.  In 551, the SA is speaking only about laundry and haircuts; these activities are permitted starting immediately after the fast.  In 558, the SA is speaking about eating meat and drinking wine; one cannot partake of these until chatzos of the 10th. 

 

Why should there be a difference between them? Rav BenTzion Aba Shaul explains (vol 3 of Ohr l'Tzion #29) that the issur to have wine and meat have nothing to do with aveilus.  Someone who is an aveil can eat meat.  The reason we don't eat them is because korbanos were meat; nesachim were wine offerings.  The issur is to help us mark the loss of avodah in beis hamikdash.  Haircuts and washing are nihugei aveilus.  Once 9 Av ends, the aveilus is lifted, but our commemoration of the avodah that was lost continues until the next day, as it was on the night of the 9th and into the 10th that the mikdash was burned.

 

Another nafka minah based on this same idea: when 9 Av falls out on Sunday, if a person has to eat, can he say havdalah on wine?  During the 9 days one is allowed the drink wine for the sake of a mitzvah, including havdalah (the minhag of beer for havdalah is fraught with complications that are a different discussion).  However, Rav Elyashiv and others held that the same is not true on 9 Av itself.  Just like m'dina d'gemara we do not allow wine in seudah ha'mafseket as a remembrance to the korbanos and nesachim, the same is true on 9 Av itself.  Even if the dinim of the taanis are suspended for the choleh, the din of having this remembrance for the korbanos remains in effect.