In my experience, there isn't a huge difference in the level of racial bigotry between northern and southern states. The difference lies primarily in the openness of it.
For example, the effects of deed-restricted home sales are still being felt today in many neighborhoods in northern states.
In some ways, the openness of the southern brand of racism is more respectable than the northern brand. While the southern real estate agent was open with you, the northern real estate agent may simply assume you don't want to live in a neighborhood that's "too black," never say so to your face, and proceed to only show you houses in the "nice" part of town.
Yes, it's a contrived example, but it's also something that happens every day all over the country.
When I was managing people in the '90s in California one of the technicians who worked for me was black and had worked all over the country.
He said he much preferred living in the South, because while there was no difference in the number of bigots he ran across, outside the South the bigots weren't brave enough to be open about it so it was harder to tell where he stood.
I think there's probably some legitimacy to that view, but I always wonder how much "shit happens" type stuff gets identified as racism. I'm white, so when a white guy is an asshole to me I assume he's an asshole. If I were black I might assume he's a racist.
Besides racism, that's also a way to say "too poor/downtrodden/crime ridden".
To which, they would indeed have a point (statistics wise), although that of course is caused by the systemic injustice and lack of opportunities against blacks for centuries.
Also notice how people still say the exact same thing about "white trash" places in the North (and South), and nobody seems to mind, because while the US got more tolerant about race, they still don't give a rats arse about classism and social exclusion based on being poor and not a "success".
There is a lot of bigotry in the Bay Area and online. Considering what we know about the mental shortcuts people use to process complex social information, evidence/science minded people should expect there to be bigotry as an unfortunate phenomenon to be aware of. Instead, it has received the imprimatur of "sin."
It's a thorny problem. Talk about bigotry in the "wrong" way, and you ironically open yourself up to yet more bigotry involving projections about your internal mental state.
I mean, sure, there are super racist areas in the south. I grew up and lived in mostly rural Alabama for the first 20+ years of my life, and there were some rural areas that were just as terrible as people imagine (cross burnings, open Klan meetings, etc, though that was starting to die down in the last 10 years or so I lived there).
That said, a lot of cities in the south are 30% - 50% black (sometimes more), and people who live in those cities, generally speaking, coexist and interact with many black and white people on a continual basis. It'd be kind of hard to do that and be super racists to the level people imagine the south to be.
Or maybe I am just bitter about a 70% white city talking about how racist a 53% black city must be.
Todd Barry has a great bit on this (language might be offensive to some) https://www.youtube.com/watch?v=HfNnM2aYsWo