Who thinks life has sanctity? Disconnecting a person who is a complete vegetative case from machines is like picking a cucumber (human emotions aside). To sharpen the point, say that someone who kills one person and causes another to be born is like someone who steals a hundred-dollar bill and gives back a different hundred-dollar bill in its place.

There is no such thing as "the sanctity of life" according to the Torah and Jewish law. There are various kinds of holiness at different levels in the Torah:

The priests
The High Priest
The Jewish people
The Land of Israel
Jerusalem
The Temple Mount
The Temple courtyards (between the Hall and the altar, the Priests' Courtyard, the Israelites' Courtyard, the Women's Courtyard)
The Temple (the Holy of Holies, the Sanctuary, and the Hall)
Terumah, the priestly tithe, first-fruits, the second tithe
Most holy offerings (burnt offerings, sin offerings, guilt offerings, meal offerings)
Lesser holy offerings (peace offerings, firstborn offering, animal tithe, Passover offering, thanksgiving offering, and the ram of a Nazirite)
Jewish holidays
Yom Kippur
Sabbaths
Maybe also the intermediate days of a festival
Tefillin, a Torah scroll, a mezuzah, sacred books

But there is no such thing as "the sanctity of life." That's cheap romanticism.