I guess the interactive redistricting map that 538 made flummoxed you?
What is it you think is incorrect?
The Florida 5th district was carved to specifically reach into black neighborhoods in Tallahassee and Jacksonville and tie them together in order to a create a district in which blacks compose a majority. If they're not combined those communities are only about 30% of their respective local populations, and thereby are considered less likely to see a black candidate win.
https://www.pbs.org/newshour/politics/new-maps-spark-debate-over-majority-minority-districts
For decades, the widely accepted strategy was to group together Black voters so they comprised a majority in a statehouse or congressional district. That principle was enshrined in the federal Voting Rights Act, which requires the creation of districts with a majority or plurality of Black — or other minority racial or ethnic group — voters in places where the white population has a history of preventing them from electing their chosen representatives.
That strategy was reinforced by partisan politics. Republicans have been happy to draw districts with large numbers of Black voters because Black voters overwhelmingly favor Democrats. The effect was to pack Democrats into just a few districts and leave other parts of the state more safely Republican.