This is a great question--because The New Chronology is popular in Russia particularly, and appeals to a specific set of nationalist ideas about the Russian empire, it maybe makes sense that the conspiracy theory would highlight a belief that ethnic Russians--blond, blue-eyed Slavs--were at the heart of all civilization. The Russian Empire is a bit different, historically, from others that we may be more familiar with (say, the British or American empires), because the idea of a Russian empire is inherently multi-ethnic in a way that those in the west aren't. While the British conceived of their empire as one where they were ethnically and racially superior to those they colonized and subjugated, the Russian Empire was always deliberately multi-ethnic, with ethnic Russians just a kind of "first among equals," so to speak (assume that a lot of what I'm saying here is in scare quotes--I'm doing my best to relay what I believe others think and obviously am not endorsing any particular racist or colonial logic myself!). The New Chronology, which is more explicitly racist in its positing that ethnic Russians are at the heart of all culture and civilization, is thus a break from the traditional ways that the Russian Empire has been conceived, and is what happens when you have an empire (in this case, the Soviet Union) fall apart and leave behind only wreckage, with people clinging to increasingly extreme and problematic theories to make sense of what's happening.