I think what's happened is that a lot of people are very invested in making sure anthropogenic global warming is accepted as fact. Some people, like Gore, are financially invested directly -- for others, like these guys at CRU, they're invested in many sure they keep getting grant money to 'study' AGW.

Science ceases to be science when you stop using your data to inform your hypotheses and start molding your data to FIT your hypotheses. I think there's a good chance that this is what was happening in the case of CRU.