Dan Klein points me to this essay by Michael Marlow. Bias among researchers is what we prefer not to think about, but it is probably inescapable. Marlow notes "good intentions bias" in his discussion of research on smoking bans.
I tell students that reading widely is the only antidote. Waiting for unbiased findings in this life is fruitless. Read widely for perspective. It's the best use of your time.
There are many findings on climate change and there are many findings on smoking bans. They all compete for our attention.
And, yes, it's all made much more difficult when arm-twisting and other chicanery are involved. Exposing the egregious cases is, of course, essential. But in the end the onus is on each of us to reach conclusions. Sharing any wisdom thereby gained is also a serious responsibility.