Same reason public executions were held in the first place. Here are a couple:So, the glasses was a protection from the supreme inari/Mogami-san? That's why the stalker exploded into ink?
Also, why in the world would the foxes bring the MC to basically a public execution? What reason is there to show him that?
-Bring the would be murder victim closure. The threat is done and over with.
-let everyone in the town know justice has been delivered
-Scare any potential criminals straight.
-integrating potential hubby into their culture and custums openly and honestly.
That's how things used to be done and for a more traditional fox society where delinquency is significantly more dangerous and has far more severe consequences then it makes sense severe punishment has been kept