Most likely he wasn't talking about forza, and more about other japanese developer racing games.
I really believe he so absorbed in his ego he doesn't even care to play Forza3 which is his truly competition.
If they do not use some features of forza like rewarding more if you playing difficult without tweaks but give option to use tweaks also, rewind feature etc, Forza may turn out the most fun game, even if GT5 is more impressive.