And you know this how?
Were you there?
Did you interview everyone personally who lived there at that time?
Are you a trained psychologist who is capable of evaluating the mental state of thousands of dead people?
Based upon the same type of evidence that Jews died in concentration camps in Germany during WWII, that Mao killed upwards of 40 million of his own people, that Pol Pot killed 10 percent of the population of his country, and that the reason for enactment of the First Amendment for freedom of religion in the United States was enacted because of the different Protestant sects killing and persecuting each other.
Are you a trained psychologist who is capable of evaluating the mental state of thousands of dead people?
I'm not sure that Calvin killed thousands of people directly. Indirectly...