There’s some nuance here though when they shoot themselves with their own firearms. That’s absolutely self inflicted “play stupid games” material. So I wouldn’t condemn people celebrating this particular type of accidents.

I would celebrate their admission of wrongdoing and willful rehabilitation to civil society. Alternatively, if the way they stop being a threat is that they happen to die, I will celebrate that decent people are safer as a result.

They are also an origination killing people and publicly celebrating the murders as an act of “counter terrorism”. You don’t sign up for the gestapo for good vibes.