Because he is a brilliant dutch player. He is strong on the attack and tenacious in defending bad positions.
How is it that Hikaru Nakamura has a 90%+ win/draw w/ Dutch Defense?

And the average opponent rating was?
Last time I remember him playing the dutch against Kramnik he was massacred.
1. d4 f5
As Black, Nakamura has won 51.6% and drawn 38.7% out of 31 games.