Nope,not idiotic at all.This year Fed has best results on clay by far which makes him #1 for this year.Similar to that so far Nadal has best results on HC this year by far(AO+IW)so he's the best HC player for this year,atleast so far as there's also USO series to be played this year.
Add to that,Nadal was the best grasscourt player last year because he won Wimbledon.
Ironic, not idiotic.