Punishment is easiest to demand when you imagine yourself incapable of the mistake.

Severity comes easily when the offence feels foreign to you. Certainty that you could never have done it removes any imaginative brake, and the punishment you would accept for yourself stops being the reference point. Distance is what makes harshness feel like principle.

Before deciding what someone deserves, spend a moment on how the mistake could have happened. Not to excuse it, but to reach the version of the story where a person, under pressure, did this. Then decide. The answer is often still firm, and usually more accurate.