There's a problem with modern skepticism.
When somebody objects to charlatanry on the grounds that its principles are wrong, that's bad skepticism. I've seen people object to homeopathy, for instance, by pointing out that the Law Of Infinitesimals contradicts known scientific fact. Bad skeptic! No biscuit!
The scientific mindset doesn't require you to prove how something works, or why something works, but that you prove THAT it works. Double-blind placebo-controlled clinical trials (that old chestnut) do not prove that a researcher's reasoning is valid; they prove that some particular testable prediction was correct or not correct. With error bars.
Knowing WHY something is, is a very different thing from knowing THAT it is. The former is deep, and rich, and in some cases might in fact be impossible (maybe fully understanding quantum mechanics, say, takes, in some inescapable information-theory kind of way, two more square inches of cortex than you've got in your skull). The latter, though, we have a chance at, and sometimes may even get a firm grasp on.
But bad skepticism happens a lot. People who think themselves intelligent, un-gullible, alethetropic, or epistemically virtuous, often engage in bad skepticism. When they should know better.
It happens because of a deeper problem. I think it may be connected to the Myth Of Reason. We've allowed ourselves to get so cocky about being logical, that we've begun attributing to logic powers it doesn't have.
Which, if we do not correct it, will make us no better than charlatans ourselves.