>Since I haven't read the books you linked too, I cannot presently make a case against their content, but If the claim that people naturally feel inclined to divide themselves on the basis of ethnicity and nationality, then I have a few issues with that proposition.>
I think the mentality you're taking is a defensive one, rather than that of a desire to reach genuine understanding. If you really care about people then you have to take the time to understand how they operate, and that means setting aside your feelings of "right and wrong" and following where the scientific evidence leads. Much in the same way that the "god of the gaps" argument prevents true understanding, the desire to discredit new ideas that seems contrary to previously held beliefs on the surface holds people back from fully grasping them.
You mention religion and state indoctrination as causal forces in the development of people's behaviour, but do you know the origins of religiosity?
People can only realistically identity with a small number of people and research suggests that groups are more likely to form with genetically similar people. Trust is a big issue for people and similarity is an important indicator.
Rather than object to views you morally disagree with, understand these views and whether they have scientific merit. Going about things in this manner can only benefit your clarity of perception.