Hooray for our side!
What the book's author seemed to me to be saying was that humans are all the same species. We basically all have the same potential (but there are individual differences in intelligence and personality traits), at least averaged over the population. But, location and circumstances matter.
"Western Civilization" wasn't a fluke- it was the natural consequence of certain natural conditions. It doesn't matter where it happened to begin, or who it began with. At least, not to me. I don't get the objection to that.
I would be living a very different life had I been born in the Australian Outback, without electricity or abundant food and water, rather than in the "American Outback" where those things are currently common. I can't begin to pretend that there is some property of "me" that would have the same skills and use the same technology and have the same opportunities no matter where I happened to be born and grow.
Because a population of humans did "luck out" and live in an area where food production could be made less time-consuming, their time was freed so that they could learn to apply the scientific method instead of spending their time worrying about where the next meal would come from- if it came at all.
So, while it may have been "lucky" that some humans were from an area where there were abundant domesticable plants and animals, and those domesticates were able to spread over a wide geographic area due to the orientation of the continent, that isn't a judgement on anyone else. I can't even claim it is "better" to be technologically advanced. I like it, but that's just me.
I would have just as much value as a person if I lived in a cave and wore animal skins. I might even be just as happy, although probably not as comfortable.
Opportunities matter a lot. Even though I am not convinced that agriculture was a good thing in the long run, saddling humans as it did with a professional class of thugs and thieves who enjoy a (temporary) veil of legitimacy.