Many look at the “The 3 weeks” as putting a damper on their summer plans and the “The 9 days” as an even heavier damper, where there are many “restrictions” including swimming, music, shaving, eating meat, drinking wine/alcohol, etc.
However, people like their meat, and, have found a way, with the help of their rabbis, to beat the system. Make a siyum, now, restaurants can be open and serve meat for all to enjoy. Many (very religious) camps do the same siyum game, inculcating our youth with this warped idea that if we really want something, we can figure a way around it. “If there is a rabbinic will, there is a rabbinic way.”
The only time chazal forbade fresh meat (meat older than 3 days is permitted - which most of our meat is) or drinking wine (grape juice is ok) is at the meal right before the Tisha B’av fast begins, seudah ha’mafseket.
לֹא יֹאכַל בָּשָׂר וְלֹא יִשְׁתֶּה יַיִן תָּנָא אֲבָל אוֹכֵל הוּא בָּשָׂר מָלִיחַ וְשׁוֹתֶה יַיִן מִגִּתּוֹ בָּשָׂר מָלִיחַ עַד כַּמָּה אָמַר רַב חִינָּנָא בַּר כָּהֲנָא מִשְּׁמֵיהּ דִּשְׁמוּאֵל כׇּל זְמַן שֶׁהוּא כִּשְׁלָמִים וְיַיִן מִגִּתּוֹ עַד כַּמָּה כׇּל זְמַן שֶׁהוּא תּוֹסֵס תָּנָא יַיִן תּוֹסֵס אֵין בּוֹ מִשּׁוּם גִּילּוּי וְכַמָּה תְּסִיסָתוֹ שְׁלֹשָׁה יָמִים
§ The mishna taught that one may neither eat meat nor drink wine. A tanna taught in the Tosefta: However, one may eat heavily salted meat and drink wine from his press, i.e., wine that has not finished fermenting. The Gemara inquires: With regard to salted meat, how long must this meat remain in salt before it is permitted? Rav Ḥinnana bar Kahana said in the name of Shmuel: As long as it is like peace-offerings, which could be eaten for two days and one night after they were sacrificed. After this time has passed, it is no longer called meat. Therefore, if it was salted for longer than this, it may be eaten on the eve of the Ninth of Av. The Gemara asks: And with regard to wine from his press, until when is wine considered from his press? As long as it is fermenting. A tanna taught in a baraita: Wine that is fermenting does not have a problem with regard to exposed liquids, as there is no concern that a snake will leave its venom in that wine. And how long is its fermenting period? Three days from the time the grapes were pressed.
Then, even more, recent scholars came along and thought, the newly minted “9 days” is not enough, let's extend it to a “3 week” period, starting from the 17th of Tammuz, effectively ruining the summer vacation.
Circling back to the meat. There is no problem whatsoever, eating fresh meat/drinking wine during "the 9 days", even at the seudah ha’mafseket one can still eat meat that was slaughtered more than 3 days prior. This goes all the way from the time of the gemara until the Rambam, undisputed.
(ז) תִּשְׁעָה בְּאָב לֵילוֹ כְּיוֹמוֹ לְכָל דָּבָר. וְאֵין אוֹכְלִין אֶלָּא מִבְּעוֹד יוֹם. וּבֵין הַשְּׁמָשׁוֹת שֶׁלּוֹ אָסוּר כְּיוֹם הַכִּפּוּרִים. וְלֹא יֹאכַל בָּשָׂר וְלֹא יִשְׁתֶּה יַיִן בַּסְּעֻדָּה הַמַּפְסִיק בָּהּ. אֲבָל שׁוֹתֶה הוּא יַיִן מִגִּתּוֹ שֶׁיֵּשׁ לוֹ שְׁלֹשָׁה יָמִים אוֹ פָּחוֹת. וְאוֹכֵל בָּשָׂר מָלִיחַ שֶׁיֵּשׁ לוֹ שְׁלֹשָׁה יָמִים אוֹ יֶתֶר. וְלֹא יֹאכַל שְׁנֵי תַּבְשִׁילִין:
(ח) בַּמֶּה דְּבָרִים אֲמוּרִים שֶׁאָכַל עֶרֶב תִּשְׁעָה בְּאָב אַחַר חֲצוֹת. אֲבָל אִם סָעַד קֹדֶם חֲצוֹת אַף עַל פִּי שֶׁהוּא מַפְסִיק בָּהּ אוֹכֵל כָּל מַה שֶּׁיִּרְצֶה.
(7) The night of the Ninth of Av is like the day in every matter. And we may only eat from when it is still day (on the previous day). And its twilight [time] is forbidden like on Yom Kippur. And one should not eat meat or drink wine on the meal that pauses [our eating before the fast]. But he may drink wine from the winepress that is three days old or less. And he may eat salted meat that is three days old or more. And he should not eat eat two [cooked] dishes.
(8) To what are these words applicable? When one ate on the eve of the Ninth of Av after midday. But if he ate before midday, even though he pauses [eating] with it, he may eat everything that he wants.
Instead of just telling people the truth, it’s fine to eat meat, there is no problem at all; they instead purvey this warped idea of circumventing what people believe is a prohibition, and cementing the concept that it just takes some manipulation, and we can do as we please.
That is not what chazal intended. Whoever adds takes away.
אמר חזקיה מניין שכל המוסיף גורע שנאמר (בראשית ג, ג) אמר אלהים לא תאכלו ממנו ולא תגעו בו
Ḥizkiyya says: From where is it derived that anyone who adds, subtracts? It is derived from a verse, as it is stated that Eve said: “God has said: You shall not eat of it, neither shall you touch it” (Genesis 3:3)
That is not what chazal intended. Whoever adds takes away.