I will say that this Tartary stuff is really fascinating, I remember going down the rabbit hole at first and being like "huh...that is really interesting..let me see more!" and I was starting to get to a point where I was almost entertaining it as a real possibility. Then I started asking myself a bunch of questions about how, why, where etc... and the whole thing kind of falls apart, at least for me.
Especially when linked in with all that mudflood stuff, which is pretty out there. I find a lot of this stuff tends to lead back to the Bible for some reason, almost like people trying to justify some part of scripture being real or whatever.
I think
@Stilton Disco brings up some great points about how present and easy to verify a lot of modern history is here in Europe and how we can see the build up of things over time, whereas the Americas are still quite recent and so don't have that long standing history to build from.
Having said all of that, recent history is one thing, as can often be based on propaganda and various biases in the readings, even from the original time. For example if you find a British news article from 1846 that tries to make a case for British conquest of various nations as the peoples there were "inferior" or whatever and needed to be "saved" etc... then finding this article is certainly a true source document from the time period, but it doesn't make the conclusions or statements therein actually correct.
Moving beyond modern history back to more ancient history is where we run into problems, most of what we think we know is often later proven incorrect and based on faulty presumptions or miniscule evidence. It tends to also incorporate biases from the people investigating as well as even propaganda from time, such as Roman propaganda about the Celts for example during their conquest of Europe. There is also often an egocentrism that "oh those primitive people's from the past couldn't possibly have done X like we do! or Couldn't have invented or used Y or were not as educated as us!".
There also seems to be a massive fetishisation of ancient Rome and the Roman perspective/view on the world/other people's as well as a lesser fetishisation of ancient Greece. For example "only the Romans could have invented X!" taken as an absolute assumption when in reality the Romans simply learned about and copied X from some other people that they interacted with/invaded etc...
And finally worst of all is the system/community of modern archaeology/archeologists and their dogmatic adherence to certain theories that either they were taught in university and assumed as absolute truths or that were revealed by a "made man" so to speak with the "right letters after his name" if you know what I mean. Egos, careers, money, grants and reputations on the line cause massive resistance to new ideas/evidence until there is either so much overwhelming evidence and the people in power so old that they are replaced and newer theories take hold. Or alternatively when someone with the right prestige, from the right institution, with the right backing finally "discovers" what other lesser known figures have presented and claims it as his own and then suddenly everyone catches up.
Not to mention the amount of evidence, documents, relics, settlements, monuments etc... that were destroyed via conquests, invasions, wars, time itself that we may never have even a half accurate picture of our origins or ancient peoples/history.
So I think definitely with ancient history we are looking at a complete shit show of assumptions and tiny nuggets/fragments of evidence, mixed with egos, biases and specific world views that must be upheld. I think people are right to be sceptical a little bit at least of ancient history etc.. especially if you come from a nation that was conquered/invaded as we all know history is written by the victors.
But more modern history is a little more difficult to fake, not impossible certainly, and even when the evidence is real the documents/people could have their own biases and propaganda.
