Pollard was an American citizen then, and only an American citizen, when he committed his crimes, and then violated his plea agreement for those crimes, for which he is incarcerated, in America. America and its various states have the death penalty, irregardless of Israel’s only occasional use of it.
That comment about Israel not having the death penalty - was in reference to all the Islamic Terrorists that Israel has in captivity, even those who have killed Israelis. Israel does not have capital punishment even for those murderers.