When Jonas's father concurs with others on the vote to release Gabriel, his compliance illustrates the disturbing degree to which people's minds are controlled and how they have been thoroughly indoctrinated and conditioned to uphold Sameness.
After having Gabriel in their home because Jonas's father has been allowed to give him more nurturing in the hope that the child would develop normally, both Jonas and his father have grown fond of this baby. In fact, the father even says one evening after Gabriel has been bathed and placed in his crib with his stuffed hippo,
"After all this extra time I've put in with him....I hope they're not going to decide to release him." (Ch. 14)
Nevertheless, Gabriel's father complies with the status quo of the community as he later tells Jonas that Gabriel has not been able to meet standards:
"...we obviously had to make the decision. Even I voted for Gabriel's release when we had the meeting this afternoon." (Ch. 21)
When Jonas hears this, he is very upset because he has learned from the Giver what release really is, and he cannot reconcile in his mind how his father could vote for release when he knows it is murder. It is at this point, then, that Jonas sadly realizes how dehumanizing and devastating to individual thought and feeling the community and its doctrine of Sameness really are.