It’s a day of Teshuva. This occured right after the first Churban, a Tzadik was killed, and right after Rosh Hashana,
If you were told that you are absolutely free & welcome to attend this game, just that you have to stay perched on a tight rope with a noose around your neck for the entire duration of the game:- How would you feel about having a place {even though with such an excellent view} on the tight rope right above the playing field?
This is not even an issue of dehydration, because after Tzom Gedaliah you can eat & drink all you wish for [other than Pas Akkum & Cholov Stam] but you will have to remain perched on this tight rope with the noose around your neck, until the conclusion of Ne’iloh.