These demoniacs are spitting at the very Sacrament of Christ's love and mercy! What hope can they have after doing that? They are practically begging to be judged by Him as an avenging King!
It's actually very similar to those who spurn and hate His mother -- another avenue of His mercy. When you throw mercy back in a good king's face, you deserve every bit of what you get afterwards.
They don't want His mercy? Don't worry, they'll get His Justice instead.
Fools! Hell is not a pleasant place, demons make the worst companions and Eternity lasts a very long time.