Of course it is, that's why books like this that try to clear existing misconceptions and challenge false paradigms with new archaeological facts and discoveries are important. The thing is, even without political meddling with the past, we still don't know many things about the world and cultures that lived centuries ago and many numbers related to that time are just rough estimates so I don't think the word "imagined" is so wrong here. It's one thing to understand that the image of the Americas being largely uninhabited mass of land with just a few wandering savages is just plainly wrong and was used to justify the means for political goals and expansion etc, but it's a different thing altogether to try and accurately estimate the actual size of native populations in cities and settlements at that that time. I mean we are still digging up "new" cities with estimated population of millions and extended trade networks that we didn't know even existed. New evidence is being added to what we know continuously so previously held views are being challenged one way or another as the overall pool of knowledge grows.