We don't exactly like to hear that. I'm sure that the people who were listening to Peter didn't particularly care to be reminded of what they had done. The temptation is to shut our ears and turn away from the Law. It's like not stepping on the scale after the holidays. Or not looking in the mirror when you don't want to see the truth about yourself.
Denial is a part of grief.
Grief is our response to death. When we don't want to deal with death, we deny it. We say it isn't so, it isn't true. We're going to beat this thing called death. But the Law says no.