The main reason being scientific consensus can lag reality significantly, especially when career incentives discourage dissent. The history of science includes many cases where consensus was wrong and critics were marginalized rather than engaged.
Deference to science as an authority is the opposite.
Feynman has a quote on this:
"Science is the belief in the ignorance of experts. When someone says, 'Science teaches such and such,' he is using the word incorrectly. Science doesn't teach anything; experience teaches it. If they say to you, 'Science has shown such and such,' you might ask, 'How does science show it? How did the scientists find out? How? What? Where?' It should not be 'science has shown' but 'this experiment, this effect, has shown.' And you have as much right as anyone else, upon hearing about the experiments — but be patient and listen to all the evidence — to judge whether a sensible conclusion has been arrived at."