What exactly do you think "rights" are but a form of social contract?
That's not the exclusive meaning of "right". Here is the dictionary definition:
"a moral or legal entitlement to have or obtain something or to act in a certain way"
The part about "legal entitlement" does indeed fit the definition of a social contract, which is all fine and good, but the definition involving "moral" allows people to get away with all sort of logical absurdities.
So, I think my original objection to the phrase "right to life" still stands.