Discrimination comes about when one person or group of people think less of another person or group because of some difference between the two. If one party considers themselves to be better than another party in some way, that is the beginning of discrimination.
In The Giver, the society made the choice to adopt Sameness, a situation in which differences between persons are eliminated as much as possible and it is made socially unacceptable to notice or react to any differences that might still remain. "It was not a rule, but was considered rude to call attention to things that were unsettling or different about individuals."
The practice of Sameness deprived the members of the community of many things. Some of those losses were unfortunate; others were positive changes, such as the elimination of discrimination.
Our people made that choice, the choice to go to Sameness. Before my time, before the previous time, back and back and back. We relinquished color when we relinquished sunshine and did away with difference. We gained control of many things. But we had to let go of others.