I do agree that is not surfing a kayak!  I don't think that those guys ever claimed to be great surf kayakers or anything, they just wanted to be in big surf to try out their new river moves.  Which they did!  There was no one around, and they were doing what they wanted in their river kayaks.  No harm done...as long as they are responsible in the lineup, even if there is none!  And there looks like from the photos that it was big and nasty (Ocean Beach, SF?) and really no one would WANT to board surf or paddle surf that crap anyhow.  Cool website from those guys though...