To add to that, the “experts” are sometimes revealed to be wrong.
That’s a terrible justification for rejecting current scientific consensus. Just because someone is wrong about X doesn’t mean that they, or another person entirely, are about Y. Furthermore, just because someone gets part of X wrong doesn’t mean that they, or another person entirely, got the whole of X wrong or that X, in general, is wrong.
Granted, mistakes and lies of the past should generate a degree of
healthy skepticism, and scientists themselves (should) possess that. Things like peer review and recognizing limitations of a study flow from that healthy skepticism. But in a scientific, or just academic sense, there is still an adherence to rigor. You study and understand the literature. You raise questions about methodology and test what you believe to be a better methodology. You may even run another person’s experiment to see if you can reproduce their results. You understand where gaps lie and how those gaps may affect common knowledge as we fill them, but you don’t necessarily see them as reasons to reject what seems established.
Groups like flat earthers, climate change deniers, and six-day creationists don’t uphold any of that. Heck, if it weren’t for the fact that they very often have political and/or religious motivations behind their skepticism, they would appear skeptical for skepticism’s sake. They often don’t understand the literature. They treat gaps in knowledge as reasons to reject what is tested. They concoct theories of grand conspiracies from the scientific community. If anything, academic rigor seems to be disregarded entirely in favor of attacking those holding to it with the ad hominem of, “They’re just biased!”
And again, this isn’t to say that we just blindly accept everything, but if we’re going to reject something, we should have far better reason for doing so than is often embraced by some of these groups.