There is no reason that even forms an argument. It just says the meme in question spreads well with fidelity - that it's a good story, i.e. one that hooks into cognitive biases in a memorable fashion - and nothing about the truth or falsity of its informational content.
This reminds me of how conspiracy theories spread. I have looked into Project Blue Beam, for example. There is a LOT of material on the web about Project Blue Beam - lots of videos, web pages and so on about it. It's quite popular on the web as conspiracy theories go. It all comes down to one short book and a talk by one person. But it captured the imagination of conspiracy theorists, and started accreting other conspiracy theories to it.
(The actual origin of Project Blue Beam - where that one person got it from - is hilarious, but I won't spoil it for you.)
Something I've been hearing a lot lately (specifically from Orthodox Jews, although it comes up a lot in debates about religion) is that having a large number of people telling a story makes it more likely the story is true, because multiple witnesses can call each other out for deviating from the truth.
My gut reaction is that this is extremely false. But it's a point that should be scientifically testable, and I figure that someone should have done a study on it by now. Does anyone know of such a thing?
A related issue is the argument that oral tradition meant something very different thousands of years ago, when it was the ONLY form of historical record. Oral historians were duty-bound to preserve the story. This sounds plausible. It probably ISN'T as easily testable since we can't compare oral history from pre-writing times against... well, much of anything. (Well, I guess archaeological evidence, if the events being described would have left enough archaeological evidence). Is there an official, accepted scholarly opinion on this?