The community in which the story of The Giver is set made a conscious decision many years in the past to eliminate differences in its living conditions and society. This came to be known as "Sameness."
Sameness means that conditions that can be controlled are kept uniform. The weather in the community doesn't vary from day to day and there are no seasons, for example. Clothing is provided by the community, and all citizens wear the same type of clothes. As the Giver explained to Jonas, "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."
Differences that could not be eliminated are not acknowledged. The standardized responses to every situation and the expectations of how residents of the community were to act supported the goal of treating everyone the same. "it was not a rule, but was considered rude to call attention to things that were unsettling or different about individuals."