There need not be perverse joy in seeing traitors and cabal actors suffer death. The joy comes in ending their reign of terror over others that suffer because of them. Killing them is the only way to end their scourge existence and warn others not to stray down a similar path.
Ultimately others will try because humans are human. But that will be for another generation to handle, just as we handle this.
In the meantime, fuck these evils pieces of shit.