It's certainly a fascinating theory. It's a bit far-fetched in places and I definitely don't believe all of it, but I do think that something happened that we aren't being told. I personally think that the people who believe Tartaria was some sort of benevolent empire are ignorant. If it is a true story, it was most likely post-flood Nephilim that ran these empires. After all, they claim that Tartaria was an empire of giants, and what are the giants? Descendants of the Nephilim.
Either way, it's just another theory I'm actually working into fiction that I'm writing. I'm sucker for alternate history theories.