There is a specific kind of internet humor that finds joy in taking something incredibly wholesome (like tea-drinking high schoolers) and placing them in a gritty, lo-fi, or "trashy" setting. Secret-Hunting:
The stark contrast between the innocent, music-loving nature of the Keionbu club members and the explicit, traumatic nature of the scenario is a primary driver.
The popularity—and notoriety—of this specific theme stems from several factors: