There's some interesting stuff in this report if you take some time with it.
But in short, the evidence suggests that a significant amount of hate crimes go unreported as hate crimes. While this report also goes by region as well, it does not specify where in the US the lack of reporting is centered.
This is not to say that these crimes A) do not happen or B) go unreported as crimes, just that they're not reported as hate crimes. A majority of these "unreported as hate crimes" get handled a different way.
So, that suggests that either:
1) Hate crimes just don't happen as often in red states. 2) Hate crimes aren't reported as hate crimes in red states. 3) Diversity of the region plays a significant factor.
And it's probably an indeterminable mix of all three.