From a very interesting discussion between Jonathan Pageau and Vesper Stamper.

From the beginning of the lockdown and universal quarantine, I kept wondering about why they took away sports.  Bread and circuses keep the masses calm and compliant.  They kept the bread flowing, with $1200 checks, but shut off all the circuses.  Why?

Jonathan Pageau answered the question, and the answer only makes sense if you knew you wanted riots all along.  Sports, like religion, is a place of identity and communion.  But it is something more.  Sports offers a place to fuel our aggressive tendencies and to give an outlet to channel our aggression.  We cheer and root and argue about our team.

The gladiators served the same purpose.  It sublimates our aggression; it's a communal catharsis of violence.  When you take it away, you end up with what you've got now: pseudo-religious actions where people are using all religious tropes of scapegoating, catharsis, violence, contrition.