Why?
It is not immutable. It cannot be transferred. How is that not inalienable?
The argument of life being an inalienable "right" is it is from God, not of from human government. It is not immutable, but inalienable, it is not transferable right.
Inalienable does not mean "non-transferable". It means it cannot be transfered, surrendered or taken.
An inalienable right is a right that cannot be
alienated.
But Scriptute says that the murderer dies.
The passage you provided disproves your claim in two ways -
1. The prohibition against murder is based on God (on God's image) not on a human right.
2. The murderer is to be alienated from his life.
There is no way around this. You were mistaken.
But if you consider the DOI to be strictly in context of government interaction with the governed then you have a human right based on restriction (the intent of the founding fathers).
Men do not have the right to take another's life. In the context of the DOI, then, our lives are protected as a right because it restricts the other.
The Constitution does not exist to give rights but to restrict government.