Honesty is such a lonely word

Honesty is such a lonely word

My son was part of some roughhousing that broke a class fishbowl. The teacher asked those responsible to come forward, but nobody did. Eventually, my son felt guilty and confessed his role in it. He was sent to the principal for punishment, which was fair. Later, the other three boys were also found out and received the same punishment. I was surprised that their punishment wasn’t harsher since they didn’t admit to it. Am I wrong?