There's an obsession with painting Hitler as a unique figure whose rise to power and fascist crimes were the result of a confluence of personality disorders, family history, his experiences in WW1. It's mainly a liberal thing because they really need the history of fascism to be the history of singular evil figures, rather than the result of imperialist capitalism eating itself. It would be very useful for the liberal world order to place blame on genetics or individual psychology for the machinations of history. Rather than the consequences of things like economic conditions, imperialism, class struggle, etc

So yeah you've got it right. For the longest time blame was placed on Hitler's supposedly hypnotizing public speaking skills. I guess now extrapolating his gene sequence is supposed to shed light on if being evil or fascist is hereditary, which itself sounds like eugenics