Since when did fact-checking become an obstacle to facts?

Matthew Ingram at Gigaom makes the extraordinary case in a post today that fact-checking should be done after the fact so that the reading public can see the mistakes and the subsequent corrections in a magazine story. His case seems to be that fact-checking would have removed or corrected the errors that Harvard historian Niall Ferguson is widely accused of in  a recent Newsweek cover story.

"If what we are after is more transparency when it comes to journalism, public fact-checking and debate is an integral part of that process...."

"My point is this," says Ingram: "Isn’t it better to have those criticisms and counterarguments out where readers can see them and inform themselves if they wish? And if Ferguson is the type of academic who plays fast and loose with the truth in order to make his argument, as Atlantic writer James Fallows seems to suggest he might be, isn’t it better that we know that by seeing his arguments in as clear a light as possible? If those errors or logical inconsistencies had been fixed by nameless fact-checkers at Newsweek, all we would really know is that the magazine has a good fact-checking department."

So let me get this straight. We allow the readers to be fed mistakes we could have caught so that, through comments, debate and coverage elsewhere (which those readers may or may not see) we can feel good about the integrity of the process?