I don’t care what their past is like or if they have brain damage justice still demands that they die.
The fact that they are somatically predisposed to murder simply reinforces the judgment that they must never again be free in society. The only way to ensure that they never again are a threat to society is to put them to death.
To permit them to live under a life sentence leaves the possibility that someday legislation or a judge will free them from captivity and they will again be able to prey on the inocent.
Watch what road you go down there, because “preventive execution” as your linchpin rationale could be extended to those who some supposed pundit has deemed likely to murder in the future even if not now. Punishment that is not “deserved” is immoral, period.
But but but but that would be like eliminating wolverines from kindergartens, just because they are wolverines!