Idk what that site bases the prices on but it's REALLY inaccurate.
Like somebody else already said, take for instance the highest valued character and compare it to some other high valued characters. One of them, a paladin with 18k+ achie points, glad titles and stuff is worth less than that dwarf rogue?
Also, (yes, this might sound stupid) if you type in other -famous- wow players like Swifty you get pretty low values. Swifty's character is like worth 6.1k I believe >.<
I know it's for shizzles and giggles, but still ;P