There are many things humans know. There are far more that they don't. A number of different theories pop up whenever a question has open ends. And sometimes when an event happens and the official story happens, people think a conspiracy is going on to hide the truth.
I do not accept nearly all conspiracy theories about most events in question. But there is a question in my mind about any time a timeline is presented as fact when all there is, is, theory and conjecture. I do not take specific issue with any theory. But I also don't consider the case closed when faced with an official explanation or theory, or facts that seem to be manufactured to make a specific case.
You might think, oh, he is a redneck gun toting rural living moron who voted for Trump. He hates science and wears a tinfoil hat. If you do, you'd be wrong on every aspect of the question. At the same time we are meant to question everything, use our own minds, and use science as a tool to help understand the various questions we are presented.
That is, I don't believe that just because a fact is presented that it is a better fact than others. Speculative theories do often make enormous leaps of reasoning. But, as a degreed historian, I know that humanity has existed for at least 200,000 years with a modern sized brain. That suggests that our 5000 years of history that we are mostly agreed upon, is a drop in the bucket of time.
In that time so many things could have happened that make our understanding of the world different. And these could be the basis of legends and myths. And we will never be able to prove them, regardless if they happened.
The average skeptic will say, but that doesn't mean it happened. Surely, that is true. But absence of evidence is not evidence of absence. Watch the power of earthquakes, tsunami, or hell how about nuclear weapons. We live in changeable world and have fragile bodies. Just because you find a skeletal foot doesn't mean you know the whole picture.
I include here pics that would be defined as those of Ancient Aliens phenomenon. They are not proof of anything but they don't fit some of the speculative definitions that science makes. So, some thinkers of odd theories filled in the blanks.
I don't believe that humans were only able to advance with assistance from aliens, as some suggest. I don't believe in prehistoric nuclear battles. But I absolutely believe that there are unknown or unknowable ages of technology that have been lost. Greek fire is just one of those unknown technologies made in the past that is still impossible to replicate. A lost age of steel could well have happened, and an earthquake or flood or plague destroyed them all. And if no one finds evidence of that, it never happened?
My point is, people call theories that divert from the official story by historians and archeologists alternative or fringe science or pseudo science. By calling them this there is a stigma attached to the alternative views, and there is no argument you can make to me that it is reasonable.
Read, think, write, explore everything. There is no "proper" thinking regarding unproven history, science or theories in general.
Some writers in the popular culture suggest that fake news helped defeat Hillary Rodham Clinton. In my mind if this is true, then the people saying it are underestimating the human ability to think. I don't believe in, and don't share news of the Fake. But how much labeled fake is truly fake? Beware of labels that try to stop you from thinking.