Surely the title of this item "A lot of what is known about pirates is not true" is an oxy-moron?

A lot of what is [thought to be] known about pirates is not true? A lot of what is [not] known about pirates is not true?

And also "A lot we know about pirates is not true..." also seems 'wrong'

But I can't work out what exactly seems incorrect. I've tried substituting 'pirates' for something else, but nothing works. Help! Any linguists around...?

I can't find anything that says that "known" things must be true. They're more "generally understood". So I don't think there's any issue with the original title.

That was my reaction too; you can't "know" something that is false. Despite my innate pedantry, I didn't comment, because it's pretty clear what the title means.