I found R. Scott Clark's very brief post (link) puzzling. He asserts, "Yes, that’s right, Calvin said “offer” (not demand) as in “free” or “well-meant” offer of the gospel." That's a rather odd way of putting it.
a) Calvin obviously didn't use English.
b) Calvin did use the Latin cognate word to our English word "offer."
c) In this place, however, Calvin used the word "offer" as a verb, not a noun - much as it is used in WSC Answer to Question 31 or WCF VII:III (7:3).
d) It's not clear whether RSC is aware of the controversy that exists over the use of the expression "well-meant offer" as contrasted to the Reformed doctrine of the freely offered gospel. If so, it is mischievous of RSC to suggest that Calvin using the word "offer" is Calvin taking a position on one side or the other of that controversy.
e) The fact that Calvin doesn't (in the particular instance to which RSC points) use the word "demand" is inconsequential. Calvin naturally agrees with Paul who states that God "commandeth" all men everywhere to believe (Acts 17:30). Thus, even though we gospel preachers offer salvation to the masses, we do not necessarily refrain from preaching that it is men's duty to repent of their sins and appropriate Christ's sacrifice by faith.
I suspect that RSC just intended to tweak the nose of one or more of his regular readers who have a scruple against using the term "offer" because of its association (via the afore-mentioned controversy) with liberal tendencies towards synergism. I wish he wouldn't do that.