Oh boy <img src="/forum/images/graemlins/puke.gif" alt="" />
Nobody has ever denied (even Dr. Horton) that John Calvin believed Servetus deserved the death penalty.
If you had lived in that day, you would probably agree with it yourself. At that time pretty well all of Christians believed that Servetus should be executed. If I have my history correct, the issue of Calvin sanctioning the burning of Servetus wasn’t an issue until much later when his critiques were looking for something (much like what you are doing) to smear Calvin’s good name.
The issue that many Christians had however in that day was making sure that people who are executed are done so in a humane way.
The problem you are having is that you are looking through the lense of modern thinking. This is that heretics shouldn’t be put to death, or even punished.
It probably wouldn't even be an issue with you had you lived in the time of Calvin.

Whether or not Christians of that time were right believing that Servetus should be executed, is not the point. For example, I used to be an Arminian but I did so because I sincerely believed it was biblical. I believe that if Calvin or any true Christian of that day became convinced that it was wrong to sanction the execution of heretics like Servetus, they would change their views.
Please don’t try and tell me that you have never believed something (as a Christian) that you now disagree with.
By the way, the positive influence that Calvin had on Geneva and the world in his life time, was one that very few could claim.