Political theorist: Many people believe that the punishment of those who commit even the most heinous crimes should be mitigated to some extent if the crime was motivated by a sincere desire to achieve some larger good. Granted, some criminals with admirable motives deserve mitigated punishments. Nonetheless, judges should never mitigate punishment on the basis of motives, since motives are essentially a matter of conjecture and even vicious motives can easily be presented as altruistic.
The principle that it is better to err on the side of overly severe punishment than to err on the side of overly lenient punishment, if valid, most helps to justify the political theorist's reasoning.