There are 7 House districts in Alabama. Currently 1 out of 7 of them are Black majority, while about 2/7 people in Alabama are Black. It’s illegal racial gerrymandering that keeps it this way. Any reasonable map would have at least 2 Black districts, so this case is explicitly about reversing gerrymandering by requiring another Black majority district.
If they created 4 Black majority districts that would be gerrymandering. As it is, it’s about making a map that represents the population of the state (something the legislature is repeatedly refusing to do).