This is an article on the origin of the USA holiday of Memorial Day. Among the interesting aspects of this observance is how many cities/towns in the US claim they are the Point of Origin for Memorial Day. And it’s also interesting how the history of these origins is slanted to support the claim. In this article, for example, it says the women visited the cemetery in October 1864 - but the original story, first appearing in 1904, claims they visited on Sunday, 4 July 1864. That claim was modified after someone pointed out that 4 July 1864 was a Monday.
I don’t think it matters where the holiday originated but the claims of the various places are really interesting.
So - I was wondering - what are some other funny/weird/persistent origin arguments you know of?