I know you're NOT smarter than this, but there is literally zero evidence that people from less diverse areas are more "intolerant" than people from diverse ones.
Dunno, the Pennsylvania 2016 county swing map is pretty compelling. For a different example, the areas that voted heavily for Brexit tended to be places that were not diverse at all or which were historically not diverse, but suddenly had an influx of migrants from Poland or Romania (e.g., East Anglia.)
I reject the assertion that there is a meaningful correlation between a swing toward Trump and "intolerance," but even so aren't there multiple studies that show racial polarization and segregation increase a heck of a lot more in areas with higher minority populations? I don't really consider a White liberal hipster who lives in Lakeview in Chicago but is too scared to ever accidentally venture south of the Loop very "tolerant," no matter what he posts on his Facebook page.
