Baltimore here, almost two decades. If the point you're using my city to make were as obvious as you make it sound, I would not now need to ask that you make it explicit.
http://graphics.wsj.com/baltimore-demographics/ http://www.baltimoresun.com/news/data/bal-baltimore-segregat... http://www.huffingtonpost.com/2015/04/28/baltimore-segregate...
It's very easy and very comforting to say that maps like the ones you linked are just a result of white people not wanting to live around black people, because white people are racist. I get that. Who wouldn't rather believe a just-so story than acknowledge that not everything is simple and not every problem has an easy solution? Just don't make the mistake of confusing a just-so story with reality, or imagining that by doing so you're very likely to be of benefit to anyone.
Likely due to net-population-availability of minority groups, and I won't disagree that many neighborhoods are almost entirely black (stayed with a friend living off diamond st one time), but I will say that one shouldn't then draw that to mean everyone in those cities also lives along the lines of such segregation. (To try and explain why the parent, and myself, had an experience that didn't always align intuitively with those articles)
What I'd also call out though that I wouldn't have noticed outside of having grown up there, is that I'd draw the lines there FAR more aggressively along socioeconomic boundaries, which just so happen to correlate with race. Not even starting to turn this into a discussion about which direction the correlation moves in, but I'm always hesitant to paint it soley it as a racial problem.
To use extremes, if 1% of a population has a PHD then holding a PHD may be a proxy for other desired things. If 99% of a population has a PHD then it's less useful as a proxy.
PS: On it's own a few years of post secondary education don't actually mean much, so a large chunk of the value is as a proxy.
A lot of people on the left now describe the latter as discrimination, arguing that only institutional discrimination can be called racism, which can make some discussion confusing.
For example, say you're black/Hispanic/Asian and you marry into a white American family. To the extent you encounter any racism it'll be the individual kind. But the assumptions people make about you as an Asian are very likely to be the most benign. Likewise, consider the reaction of a typical Asian American community to a young Asian woman dating a white man versus a black man. Among the (cosmopolitan, upper middle class) Asians I grew up around, the former would be pretty non remarkable. The latter would still be kind of a scandal.
That's why it's socially acceptable to make fun of Asian stereotypes but not black (and to a lesser extent Hispanic) stereotypes.
However black Americans have had the weird status of being majority in some states with a unique subculture and history while also being a tiny minority across the entire country. Now mix in relatively recent interstate migration and race mixing and their subculture has an interesting problem where if they integrate, its always better for every individual, but then their unique culture and history as a group will be annihilated. White people and "americans in general" have a variety of social signalling goals they share and the black folk in cultural self preservation mode will self police to maintain their unique non-white non-american-in-general accent, views about education, work, religion, food, criminality, even down to card games and sports. See also the culturally sensitive area of insults like "acting white" and the concept of being an uncle tom.
Meanwhile for the majority locals, all of us came from groups that immigrated and integrated and created our own shared mythologies about all kinds of ridiculous stuff. Someone who insists on being an unintegrated Polish patriot, for a random example, is seen as inadequate to integrate or too dumb to successfully socialize or at best misguided, but either way is going to get a really low social status from the integrated americans. There is some "slap in the face" animosity, what we're not good enough for you?
So you can see the source of the stress in this unique situation. If they integrate and become Americans, that's likely extremely good for them on an individual level, but then their culture would literally be annihilated from the planet because there is no reservoir of afro-american culture other than the state of Mississippi. If they don't integrate, intentionally or by failure, they'll be seen as extremely low social status by descendants of those who successfully integrated. So we end up with a crazy love hate relationship can't live together, can't live apart, tons of drama.
The final cultural lesson is everyone already involved kinda knows of this uncomfortable situation so its hopelessly socially inappropriate to discuss outside some hollywood comedy or drama movies. There's a lot of pressure from both sides and the pressure is worst on those least capable of handling pressure, that being young folks full of hormones and lacking in wisdom, patience, and logic. Meanwhile other folks think the problem exists solely so they can get into social media holiness signalling spirals which doesn't really help anyone on any side. And there's plenty of racists on both sides with varying ratios of liking their own folks and hating the other folks egging things on. So the map drawn for foreigners has "here be dragons" for good reason.
One small correction: Blacks are not the majority in any state. Mississippi has the highest percentage, at 37%, but it is still 59% white.
The Blacks political problem doesn't help the situation. They're extremely politically polarized. If 95%+ vote democrat that means there will never be any internal competition in running their homelands which results pragmatically and historically in ridiculously incompetent small governmental bodies which results in failure. Meanwhile on the larger stage minorities can be kingmakers if and only if they are not polarized, polarized equals marginalized. The D party knows they'll get 95%+ of the vote regardless what they do or promise so they have no motivation to do or promise anything for Blacks. Meanwhile the R party knows they'll get rounding down to 0% of the votes no matter what they do or promise so they also do nothing for Blacks. Net result is Blacks will never have any political influence on national politics until their voting records are closer to 50:50, or at least further from 100:0, until that happens they are disenfranchised above the local level.
That is a side cultural issue in that no one wants to live in a dysfunctional local government if they can avoid it, and disenfranchisement at a higher government level means their unique concerns are going to be eternally ignored if not actively worked against, and neither trend helps integration overall.
The situation in the USA is somewhat similar to the townships system in the bad old days of South Africa, just unofficially. That system wasn't really conducive to integration or positive race relations in general.
This was by design: read up on the "Southern Strategy" if you'd like to get a better understanding the recent history between the GOP and African Americans. The Republicans found it politically expedient to oppose the civil rights movement, yet before this, the Democratic party was the party of the KKK.
One of the things I've always found shocking about America, as an Asian immigrant myself, is how black people are treated as more foreign, in their own country, than actual foreigners. There are small pockets of unintegrated Asians (mostly first generation immigrants) but cities all over the country are highly segregated along black/white lines. If you really want to understand what makes American culture tick, live somewhere like Philadelphia or Baltimore for awhile.