what about the society is revealed the reaction to eye colour?

When Jonas's father brings Gabriel home, Lily notes that the newchild has the same pale eyes as Jonas, which Jonas resents because society does not consider it polite to mention when an individual is somehow different from others. Most people in the community, with the exception of Jonas and one of the Fives, have dark eyes, and Lily speculates that Gabe and Jonas share a Birthmother.