Well, and to be fair it's not the kind of word you'd come across commonly in a newspaper as it clearly renders a firm opinion on something. Not that the global news media is exactly the prime example of unbiased reporting it might once have been, if it ever was, but it's still the sort of thing you'd read more commonly in an opinion piece or in personal conversation or in fiction. But you know it can't be too far from common use since I bet almost everybody here, despite probably not having had much reason to use the word very often, knows what it is without having to look it up. You say "charlatan" and the average person knows exactly what you're trying to evoke by using the word. So it may not be something you see all the time, but infrequency doesn't put it outside of the general English vernacular.
(And yes, I know, useless debate ... I just like talking about languages.)
