Many people were banished, and hence, left alive. Most who disagreed with Calvin were banished and not killed. Your example is invalid. I do not want to mischaracterize John Calvin. He was no more murderous than Henry VIII, Bloody Mary, or Queen Elizabeth. (In fact, he was likely less murderous than those three - even when taking into account differences in population and time "in power") Comparing him to Charlie is a very poor and overly inflammatory example. The environment created actually prevents an actual situation where people can properly discuss the matter without the flaring of emotions.
Calvin's "rule" was as complicated as his Institutes. It is a subject that has to be read to fully understand because he didn't rule like other kings would. He was more of a puppet master. If you don't thoroughly read this complicated case, you will come out with one of two opinions.
1. John Calvin is Charlie.
2. John Calvin is completely innocent.
Neither is true and a more thorough study will show that the true John Calvin is somewhere in between. He definitely did not try to imitate Christ.