Gabe is actually extremely important in The Giver. Discuss in relation to events during the Second World War.
According to the eNotes article on the Historical Context of The Giver, Lowry wrote the book "against the backdrop of events in Bosnia, and in particular the ugly results of 'ethnic cleansing.' " It is not inappropriate, however, to interpret the book in the light of World War II and the Holocaust.
Gabriel can be considered a Holocaust survivor. He had been selected for release, just as concentration camp inmates were selected for the gas chamber. In releasing Gabriel, Jonas's father would have just been doing his job--the same excuse Nazi war criminals gave after the war.
In an interview for BookPage (linked below), Lowry said that one of the influences for The Giver was something her German-born daughter-in-law said to her: "It's clear to me how we have to tell these terribly painful stories. No one knows that better than the Germans."