The New York times contains a brief article entitled One Pot describing the Spanish dish known variously as cocido or olla podrida literally "rotten pot" According to the dictionary of the Real Academia Española, podrida may have an admiring connotation, similar to the use of "filthy rich" in English. Curiously, instead of the correct podrida, the article gives the name of the dish as olla poderida, which it explains as a derivative of poder "strength", because it gives you strength.
Reader Jim Gordon wondered about this and emailed the author of the article. Her response: she and her consultants and editors were aware of the correct name and etymology but thought that some readers might be put off by the notion of rotten food, so they changed the name a little and made up a fake etymology. It seems clear that they were not trying to deceive anyone with evil intent, but I am still taken aback that a respectable newspaper would make up a fake name and etymology.
I think it's like the Eskimo snow words myth... the truth doesn't matter, what matters is what the fake story says or implies about human nature. The National Treasure etymology seems to say something profound about how history remembers people, so that's what people want to believe is true.
...but this NYT article is not a case of a folk etymology that is popular because of what it suggests, it's just a deliberate lie for no reason.
And that make all the difference. If they had simply passed along a folk etymology due to sloppy fact-checking, that'd be forgivable. Making stuff up—even for something as inconsequential as this—really bothers me.