It's the same as a court cases' expert witnesses. You pay enough you get what you want to hear. Both the extremists and the corporations fnd thier paid spokesman, I mean scientists. Even if they have to blatantly lie and falsify results. I think junk science is being kind. Where is the actual truth? Most of the time somewhere in the middle. Sometimes, rarely the product is so bad even the most corrupt are afraid to say it's OK. DDT, dioxin laden herbicides come to mind. But they never made it public, they just quietly told the government, er uh, you might want to discontinue using this product. But we bought so much of this toxic crap, now what? Hey use it in the local government and public sector, they don't know any better. That is not propaganda, that is actual history.