For anyone not familiar with the origin of the ¡El Assico! name, it is a play on the name of one of the greatest rivalries in all of sport, Real Madrid vs Barcelona FC, ¡El Classico!. The ass part comes from the fact that historically CyHawk games are generally pretty ugly examples of football. Low scoring, bad offenses, weird turnovers and self inflicted wounds, and an outsized impact from special teams.
The general population won't adopt it, because they don't get it. For dedicated (and heavily online) college football fans, it is a term of endearment at this point. ¡El Assico! is appreciated for being a weird and quirky rivalry that plays in a generally lackluster part of the college football schedule.