it's because we're trusting politicians and we're not trusting the scientists and listening to people who value logic and truth over emotional persuasion. Politicians are the problem. The incentives are not aligned properly at all.
scientists are not saints, and neither gods aware of everyone's needs/desires/preferences. They are corruptible just like anyone, including climatologists:
http://www.naturalnews.com/045695_global_warming_fabricated_data_scientific_fraud.htmlthat's why is probably better not to let anyone to take decisions for you.
The thing is that in science it shouldn't matter in the long run whether someone lies or fabricates data. Because the core of science is based around reproducibility and peer review. Over time the truth comes out. If someone is going to be making decisions based upon evidence and peer reviewed studies that have been independently verified multiple times, then it would be silly to think that I'm going to be better at making a decision based on nothing but my own emotions or ignorance.