This is just another version of the Atlantis myth, only with more pseudoscientific additions.
Sort of, but Not really.
It's actually pretty fascinating.
I've watched all of his Joe Rogan appearances, as well as this entire series.
I don't agree with all his conclusions, and think he needs more evidence, but He's showing that humans were doing things that were once thought impossible for them to do that far back. Some of what he talks about is definitely true. These people seemed to know some things that we didn't think humans back then would know. There were civilizations in the Americas before we thought there were.
His theory is that there was once a lost civilization that had higher tech levels than we previously thought. Some of that, there is actual evidence for. Some of these megalithic structures pre-date when humans should have been capable of constructing them.
The reason the left is losing it, is because by challenging the mainstream narrative, they think it encourages conspiracy theory thinking, and because they think things like this and ancient aliens is racist. Ancient aliens especially, because it claims Egyptians didn't build the pyramids.
Graham thinks survivors of a lost civilization traveled around and taught techniques to the post ice age civilizations, which is probably nonsense, as there is no real evidence to back thay up.
Edit: and holy shit xenforo just keeps getting worse on mobile. This just will not display where I am typing so it's about impossible to edit and fix posts. Might be done with TS for a while.