That's not what extraterritoriality means -- it refers to having your citizens/property be immune to local laws in foreign countries, not applying your laws to foreign citizens/property in foreign countries.
TMI is pretty secular - the author treats Buddhism more as a source of sophisticated ideas about meditation than a religion with goals that readers should adopt. I think there's a chapter in the appendix about loving-kindness practice but most of it is a non-religious guide to how to meditate. It is focused on the goal of enlightenment, but you can still benefit from it even you're not aiming for that.
But you've got to be careful not to make the mistake of incorrectly accusing someone of committing Lewontin's fallacy. Saying that race isn't real is clearly wrong, in the sense that people reliably fit into racial categories.
On the other hand, the other claim (race has no discernible effect on behaviour) isn't fallacious (at least if Lewontin's results are accurate). If there is much greater variance within populations than between them, then it is foolish to make decisions about people based on their race, as it gives very little information about them.