…when the status of Tisha be-Av is argued frontally and ideologically, the result is friction, dissention, and a status quo stalemate. The most significant changes, however, occur underneath. Without mounting a structural assault on Tisha be-Av’s rules or underlying premises, communities have refashioned the halakhah to fit both their religious sensibilities and political commitments. Thus, the day that classical halakhah portrays as a forlorn emptiness, devoid of community, Torah, and song, is now commemorated—we might even say celebrated—through Torah study, community building, and song.
Chaim Saiman, “How Halakhah Changes: From Nahem to the ‘Tisha be-Av Kumzitz'”, Lehrhaus (31 July 2017) [http://www.thelehrhaus.com/scholarship/2017/7/30/how-halakhah-changes-from-nahem-to-the-tisha-be-av-kumzitz]