Essentializing is usually conceived as a sin against members of groups - e.g., essentializing women as naturally neurotic and agreeable. But essentialize is based on "essence", which means "the basic, real, and invariable nature" of something. And it is in that sense that I see a tendency for some of us to interpret a person's moment of insensitivity, provocativeness or even hate as proof of their essence, as if whatever appeared to be benign or good-natured before was just a sham that obscured what the person "really" is.
And so we get "aha - got you pegged!" The essence of essentializing.
And so we get the unforgiving and vindictive nature of the shaming culture. Perpetual punishment for the perpetual sinner. Forgiveness and redemption are not an option when it is one's "invariant nature" to sin.