It has been a long time but I remember hating it too.
One, the whole premise about writing letter to Chinese Prime Minister makes no sense. Are Chinese Stupid? Or are they little kids? And Adiga/narrator is warning how they should be wary of this creepy Indian man who's luring them with a candy?
Two, it felt like the author is suffering from inferiority complex about being Indian or something. The book is filled with incoherent and pessimistic rambling about how living in India sucks and how China is better than us etc. Adiga/narrator is a naive person who thinks China is not riddled with poverty, corruption and nepotism. Given a choice between India and China, I'd choose in India any day.
It was like a worse Slumdog Millionaire but written by a bitter and cynical Indian. At least former made some sense considering Danny Boyle handled that film from 'Bollywood-as-a -genre' angle instead of using and sticking to one genre.