I am sorry Menagerie, at the moment, I do not feel as there is anything to apologize for. As was stated in my post, the quote was given in irony with respect to someone else had stated about Michael Servetus. Furthermore in that post I CLEARLY stated, "not being a qualified historian, I pass no judgement on Mr. Calvin with respect to the Servetus issue. The quote may or may not be accurate, what you are asking for is impossible, much like the atheists claim when debating believers and speaking of "first causes" it leads to reduction infinitum. (Please do not think I am equating you or ANYONE with atheism just a simple analogy). The quote was intended to demosntrate "irony" with respect to the discussion at that moment. Perhaps an ill timed effort at levity, but nothing more.
But you quoted it as if it were fact. I challenged that fact and you cannot show that it was Calvin who said it. I'm sorry but it is not levity to accuse someone (who apparently seems to be an enemy of yours) of saying something as offensive as you quoted - especially when the link you gave lied and said that Calvin burned anabaptists at the stake. It is obvious that the two are tied together and you absolutely pass judgment on Calvin with respect to the Servetus issue. You did so by posting an unfounded quote.
As Rippon said, a simple "I'm sorry, I was wrong" would have sufficed but instead you say "There's nothing to apologize for." Most of us see otherwise.