That is true, though considering that the Northern states, while treating African-Americans somewhat better than the south did, were still very bigoted and cold towards them until the 1930's due to their service in the Great War, I don't think we could've gotten rights too much earlier unfortunately. Heck, major cities in the north like Detroit and Pittsburgh still needed to be forced open by the Guard to enforce desegregation like in the more well known Nashville and Omaha scenarios.
Maybe if emancipation happened earlier, rather than a slow phase down that ended in 1876, this might have sped up the process. But considering how close states like Kentucky and Missouri were to swapping sides, and how we wanted to get the South back up and running asap, I can't see that happening.
Erm.....there are a few issues here that I need to address:
For one, Missouri and Kentucky did not really come all that close to switching, as a whole. Now, granted, there were a fair number of C.S. sympathizers in western KY, and in southern and eastern Missouri(especially around Cape Girardeau and Festus, if one remembers the attempted burning of Ste. Genevieve in Feb. 1864), but neither of these states would have seceded outright, not without a POD going back a bit, especially not in Missouri's case; many of the Protestant Prussians in that were sympathetic to the Confederacy, but they were a statistical minority, and nearly everyone else, including the Catholic German Americans, strongly disliked them.
Also, you are also overplaying Northern racism/prejudice a bit as well(yes, yes, I may be a leftie, but bear with me!); I am not saying it did not exist.....sadly, it did, but overall, it was usually far less severe and rather more casual than in most of the South.
Furthermore, I would add that a majority of white residents in not just Pittsburgh, but also Detroit and Omaha as well supported desegregation(though it was never mandatory, or formalized in any northern states outside of Utah, Ohio, or Idaho, and Ohio did not forbid individual counties from not allowing segregation, and Idaho's 1909 law was mainly targeted for Mexicans and Japanese, as African-Americans were about 18% of the population, and only 4% for Mexicans.) by the end of the 1940s; in fact, the large majority of the 5,000 rioters in Omaha in particular were directly affiliated with the White Citizens' Council, a group that became despised by most Americans by the '60s.
Now, granted, this didn't stop crooked real estate brokers and companies from trying to foul with people's land values or bad cops from abusing black and Latino citizens in disproportionate numbers, but the Civil Rights Act of 1952 was a good start.
I should mention, too, that when the Supreme Court upheld the 1952 Kefauver Bill(died in committee in March '53, passed in July '56 in 1956, which allowed for the nationwide recognition of interracial marriage, despite about 63% of Americans solidly disagreeing with interracial marriage as a concept, according to a 1990 research paper done by sociologist Jack Sobell from the University of Northern California, Santa Clara(a original Gallup poll from 1955 put that number at 87%, though that is now widely understood to have been inaccurate.), very few major incidents of unrest were reported outside a few cities in the South, and Ogden, Utah.....which definitely says something.
OOC: Just trying to help keep things realistic, that's all.