Why is Jonas so adamant that Lily is not angry over the playground infraction, just impatient and exasperated?

In Chapter Seventeen, Jonas has begun to see colors all the time knows, and he knows a great deal about Elsewhere through his memories. His feelings now have more depth than those analyzed every evening. Lily's story about the boy who broke rules in the play area was exasperation rather than anger.... Jonas understands this because he has now experienced "knowning" cruelty.... something that he could never discuss calmly at dinner.