It is not his responsibility to tell a batsman not to walk off. It is the umpire's responsibility to adjudicate all decisions, and Haddin may be unsportsmanlike for doing this but he is not a cheat. Rather hypocritical for Indians on here to say this stuff about Haddin when Dhoni is notorious for being a bad sport himself in much more clear cut situations than this one.
Considering the fact that Haddin has in the past immediately admitted that catches dropped short when it looked close to spectators and the umpire, I wouldn't be so sure that he knew about this. He has proven to be a good sport in the past.
I take strong objections to the opening post, which attacks the country as a whole for a supposed history of cheating just because of the underarm incident? Time to move on don't you think irrotev? It was a lifetime ago and any history certainly has no bearing upon the actions of current players.