The 'Real Time' host was making a case that you can't make assumptions about people just based on where they're from or what their political views are ... and for that matter, he says assumptions are out the window because we've become a VERY complicated melting pot.

He points to J.D. Vance's grandmother ... did anyone know Vance as a young boy thought he might be gay and his grandma told him back in the day God would still love him?

More evidence ... he says the image of farmers as Ma and Pa Kettle is ridiculous -- farmers have iPads, they believe in climate change and they're just like city slickers.

Kansas -- intolerant, right? Well, as BM points out, they voted for abortion rights and have a woman governor. California has NEVER had a woman as governor.

But music ... music is the great unifier, and Bill specifically points to country. It used to be a s***kicker's dream, with shades of racism. Now, Shaboozey is #1 this week on the country charts.

Luke Combs performed at the Grammys with Tracy Chapman and the audience loved it. Post Malone and Beyonce are making big waves in country.

So it's all complicated. So Bill says, enough of the assumptions about the people we think we know. Don't hate, at least based on what he says are outdated theories that everyone fits into a nice, neat box.