Remember that the division you see is amplified by polarizing voices that are naturally amplified by the medium that is the Internet. If you actually traveled to the US, did a long road trip across the country and sat down and talked to actual Americans, I expect you will find that the vast majority don't have strong opinions about who runs the country. They just want to afford rent and groceries.

Also if you think nerdy people who hang out on HN are immune to being "belligerent, closed-minded and judgy", you haven't worked with many nerdy people. We technical/intellectual types tend to be very logical and rational, until we're not.