From so many tragedies in Jewish history, why do we mourn the death of the 24,000 disciples of Rabi Akiva - is it because they were Tora giants ?
Many Torah giants have died in Jewish history, but based upon many conclusive & convincing rabbinic, historic and archaeological sources, I strongly agree with those that say that the 24,000 students of R. Akiva were murdered, as R. Akiva himself, by the Romans in the Bar Kochva rebellion which took place precisely at that time (122-130 C.E.). [Otherwise, since when do plagues only strike young & strong yeshiva boys more than the elderly and babies?] We know that R. Akiva and his yeshiva were the most active participants and supporters of that rebellion (see Y’rushalmi Ta’anit 4 5; Rambam, M’lachim 11, 3; ibid, Ta’aniot 5, 3; Igeret Rav Shrira Gaon, edited from ancient manuscripts by R. Dr. B.M. Lewin, and much more). This explanation has been around a long time, but the problem is that either the Romans or self-censorship removed almost everything about the rebellion from Chazal. Iv'e myself published in Hebrew on the topic after finding additional proofs: https://www.machonso.org/hamaayan/?gilayon=53&id=1560. In the brief scope of this framework, I'll just point out that the Talmud Y'rushalmi and Rambam there state that R. Akiva & all of the greatest scholars of his time (who were his 24,000 students and the central yeshiva of the period) were the leaders of that rebellion. Accordingly, the Rambam writes that the crushing of the rebellion after several years (!) of independence, and the disappointment of the great hope they had to build the Third Commonwealth, was a historic & national (!), not just a yeshiva, tragedy, which the Rambam likens to the destructions of the 2 Temples! Accordingly, it's totally understood why this period's customs resemble the 3 weeks where we mourn the destruction of the Temples, and is not "just another tragedy". I'll also point out for those who are looking for the Torah-true and genuine approach to Judaism, that these holy rabbis, whom we respect as THE transmitters of the Oral Law, were "Hesder Yeshiva" boys, combining Torah with army service just like Moshe, Yehoshua, David & all the Tanach heroes, and were far from the exile galuti Torah taught at the Lakewood and Mir yeshivas.