And originally you could use multiple Fortunes in a turn and well doubling doublers is always trouble (Throning a Throne isn't actually doubling a doubler, person who thinks of that; however King's Court on King's Court is).
I assume this is the quote you are referring to?
I'm not entirely sure what he means here, but if I had to guess, I would assume that he is referring to the fact that Throne-Throne-action 1-action 2 has (nearly) the same effect as Throne-action 1 followed by Throne-action 2. Whereas KC-KC lets you triple three actions, instead of KC-action 1 followed by KC-action 2.
I agree, though, that was a weird way to phrase it. Technically Throning a Throne is doubling a doubler.