Shades of grey
It is risky to oversimplify science for the sake of a clear public-health message.
The problem with simple messages and black-and-white statements is that they tend to be absolutes and so the easiest to falsify. The line that the science of global warming is ‘settled’ must have seemed like a good idea at the time, and when taken to refer to the narrowest of scientific questions it is correct, but it was (fairly) interpreted as insistence that no queries remained. Even legitimate debates on outstanding issues — climate sensitivity, say — can now be painted as unsettling not just to the scientific position, but also to the policy response it demands.Scientists or I should say "scientists" who make claims which go beyond what the actual data says, think that they are furthering social good. They are not. They are trading in credibility for short term goals. Ultimately, a technological society depends on belief in the truth of science. The foisting of junk science has the result in all of it being seen as garbage.