The common assumption when people say "dictated by historians" is that historians are of one accord, as if there's some giant book of "official history" that a historian's job is to keep up to date. When the public gets a hold of some tad of info that contradicts this supposed scripture, people often turn to sensational proposal. Hence "archaeologists puzzled at..." or "what your history teacher didn't tell you!" Public conceptions of history are very important to record, but they cannot be confused with academic history. Unfortunately, this is a difficult border to police. It's hard to say "We value your thoughts and ideas about Native American history" while turning to another fellow and saying "No, these ancient stones weren't carved by aliens, spend four years studying those stones with xrays like I have and then come give me your input." Like so many academics, historians can do a better job of publicly sharing their studies. But, again, like so many other studies, people want things from history it can't give. They want Neil DeGrasse Tyson's stories of medieval martyrs for science, men excommunicated for daring to use reason. Academics that tell you that they were actually booted from the Catholic Church for not believing in the divinty of Jesus are just ruining the fun. In the same way, public science is quasars and cool microbes and Did You Know factoids, rather than table after table of chromotography results.