Because they won't get to be in charge of it.
We need to let the candidates duke it out until there is only 1 left standing. Voters in every state deserves their say. Why is it necessary for the media talking heads and their country-club Republican bootlickers to crown one of their own boys early? Because they want to make things go their way - which is business as usual. In times past people didn’t care enough to get involved, so they got away with this. There is much more at stake now and people are paying attention and they don’t like what they see, that Romney is the Republican version of Obama. Because Romney is a rich Fat-Cat Republican out of touch with ordinary folks struggling to make a living, Obama will demagogue the hell out of him and eat him for lunch.
Because they won't get to be in charge of it.
I think that's the right answer. My understanding is that in a brokered convention, all of the soft delegates are free to vote again which means Newt can rally people to his side and display one on one his command of the issues.
I personally believe Newt will win the crucial independent voters in debates with Obama. Right now many of them see him as 'mean' but after a one on one debate I think it will become clear that he will be the better occupant of the White House.