I knew the story about the Havel’s greengrocer but I didn’t know the part you have quoted. Something made a click on me while reading this part. I thought «this is completely what happens in an honor society», also known as «shame society». (https://en.wikipedia.org/wiki/Guilt-Shame-Fear_spectrum_of_cultures)
For example, in traditional Islamic societies, the honor killings work this way. It is not that fathers want to kill their promiscuous daughters (and, in fact, they don’t do it if their promiscuity does not become publicly known). It is that, if they don’t do it, they are dishonored, that is, suspicious of being as immoral as the daughter. Since the family is dishonorable, nobody want to marry the other daughters (because the man marrying one of these daughters will become dishonorable too and, hence, an outcast)
That is, dishonor is contagious and the only way not to be infected is to punish the dishonorable, even if one does not want to do that or does not believe that.
I guess that, unlike traditional Christian societies (which tend to be «guilt societies»), the post-Christian Western society is becoming a «honor society» («shame society»), such as Islam. Of course, the moral is the one defined by the clergy: in Islam, the clergy is the imams while in our society the clergy is the Cathedral (media, academia, politics, etc).