> Fun fact 1: since most people are raised by their parents, religion and political party affiliation are also highly heritable, but no one is suggesting that there's a genetic basis for religion or political views.

Religious and political views being influenced by genetics is not only a completely valid hypothesis, but the most likely. Cultural environment is downstream of genetics, and although cultural memes look like they evolve, they're trickster replicators: subservient to genes.