The fact of the matter is that people who use the phrase "settled science" are almost always trying to persuade someone not to pursue a course of action that is almost certainly doomed to fail, either individually, or as a matter of public policy. You can call that "trying to manipulate the public" if you like, but this is disingenuous because it implies there is something sinister going on. There is nothing wrong with "trying to manipulate the public" to steer them away from charlatans and crackpots.
Why are you so willing to vigorously defend them and deride opposing views as charlatans and crackpots? What have these politicians and media personalities done to deserve your undying loyalty and trust?
No, as in: the people saying "the science is settled".
> Why are you so willing to vigorously defend them and deride opposing views as charlatans and crackpots?
Because the vast majority of people who challenge established science are charlatans and crackpots.
There are legitimate challenges to established science. All scientific progress starts that way. But mounting a legitimate challenge to established science is hard. It takes a lot of work. And most people I see doing it are just lazy bums who are not willing to put in the hours. They aren't even willing to put in the effort to learn what a legitimate challenge to established science even looks like, let alone actually mount one themselves. They just latch on to some fad and then bitch and moan about how "those in authority" are repressing them or some such bullshit.
In the meantime, there are a lot of hard-working actual scientists toiling away in labs around the world to do the research that actually advances human knowledge.
That's why.