Even though I don't care much about the Davis Cup, it's admirable that he sacrifices himself for his country. Maybe it's a bit extreme if you end up missing a Masters event, though. Even though I'm a big fan of Dolgopolov, the same can't be said about his national pride. He won't play in the Davis Cup because he's not getting played enough money.
I've found this post: Indian Wells Entry List/Fact Sheet (updated March 9, 2011)
. It says flu and DC team loss depression. Poor guy, I hope he feels better soon.
It is indeed a bit extreme to miss a Masters event, but I can understand why players prioritize Davis Cup. I've been there a few times (to support my faves, cause I think it's stupid to suddenly support players I don't like just because they are Dutch.
) and the atmosphere is amazing. That alone would make me want to play DC if I were a tennis player.
As for Dolgopolov, I don't have national pride either (I feel more 'general European' than Dutch), but just for the money makes me go