But who? And what questions do you ask? Without a baseline, you're poking around in the dark. Or knocking on the same 20 doors at the same 20 universities, and all those people talk to each other and they and their students all sit on each others' grant review committees. Etc. And when two scientists disagree about the evidence, how do you determine whether one of them is a total quack? Or do you just report everything that everyone says as long as they say big words you don't know?
It's really easy to be unproductively skeptical. Never believe anything. Everything is a lie or a conspiracy. That's not particularly productive, though, because although it protects you from lies and bad actors it will never get you to the truth.