I have a reason for the capital punishment. I think it's the only thing that the cabal satanists understand which would deter them. They think that they would be released from any other punishment due to their connections and that punishment does not apply to their kind, but, crazy as they are, they do understand that capital punishment means that they don't win in the end.

It is an effective deterrent to cabal behaviour in the future if the current crop of the death cult cabal all lose their heads. The future cabal will see that no matter what spells they cast or dark forces they align with, they'll just end up with capital punishment for anti-human plotting, crimes against humanity.