How does being told a lie alter Jonas's perception of adults?

As Jonas gains perspective with each training session, there comes a time in chapter 19 when the Giver decides to reveal the truth about their community to Jonas, who is under the impression that no one is ever purposely harmed by members of his community and everything is done with good intentions. In regards to the release ceremony, Jonas's parents speak casually about it and Jonas's father makes it seem like it is a happy, positive ritual that is essential for the community's stability. In chapter 19, the Giver shows Jonas a recording of a twin infant's release, which is performed by Jonas's father. Jonas is shocked, disgusted, and horrified to witness his father lethally inject the helpless infant and casually dispose of its body. Jonas is traumatized by the experience and immediately expresses his desire to flee the community. Jonas angrily tells the Giver,

"But he [Jonas's father] lied to me!" (Lowry, 79).

After being lied to by his father, who made it seem like the release ceremony was a positive ritual, Jonas refuses to spend the night at home and comes up with a plan to escape the community.

In Lois Lowry's novel The Giver, the main character is a boy named Jonas, who is about to turn twelve years old. He lives in what seems to be a utopian society (which is actually quite dystopian), where each child essentially becomes an adult in their twelfth year, when they are assigned the profession that they'll have their whole life. 
Because Jonas becomes the Receiver of Memory, his eyes are opened to the truth of just how his supposedly utopian community operates. One of the major rules of the community is that lies aren't allowed, but before Jonas begins the process of taking on memories, he is told that he is now allowed to tell lies. Over time, as he takes on more and more memories, and becomes more aware of the realities of human emotion, he realizes that adults, including his parents, lie all the time. These lies add to his new perception that the adults in his community live false, shallow lives.