The reason is because we are filled with emotions and always have biases in everything. Though this is a singing contest, there are people who will vote based on looks, who will vote because someone is so humble and not proud or maybe because they belong to their state.
As ordinary people we have no knowldge of music with the exception of a few, and that is the reason why every show has judges. We rely on their comments to base our decision, but unfortunately in II all the judges are contradictory, so noone knows who to listen to - Udit, the legendary playback singer, Javed- the master of words, Anu- the great music director, or Alisha - the pop queen/playback singer.
But I think in II even ordinary people like us can distinguish who sings good or bad. But still there are people who bring in character attributes to put these good singers down and support their favourites.
Let the underdog with the most humble personality win. We have seen the fate of an underdog last year, we will witness it once again. Karunya too as crticized by certain people who mentioned that he was proud due to his training, not so good looking, didn't sing from the heart, ete etc and other ridiculous comments, though everyody knew he was the best singer alongwith Amey. He didn't win the title, but did he really lose? Who sung a solo song in a hindi movie and that too hardly after the show was over, who is doing playback in his state, whose album are people awaiting, whose hosting musical shows? I suggest let the good singers get voted out because in the end it is these singers who will be most successful.