Is the scientific method the reason only 6% of scientists are Republican?

No, I think it has more to do with the antagonistic focuses of science and politics. Science deals with what is and isn't true, but politics deals with what they can convince the majority of people into believing what is and isn't true. Scientists tend to be disgusted with clouding of truth with what people believe to be truth and tend not to concern themselves with politics very much, especially with what pes for conservative politics in America.