I think you are over estimating the influence of "FReepers". The "we will go third party" or "we will sit this out" faction here on FR constitutes a small minority of ideologues and purists. They by no means represent the large majority on FR who will vote for their favorite candidate in the primaries and, then, join together in the general election to defeat Obama.
You are correct. I voted for McCain but did not like him at all but voted and I will do the same in this election.