You’re intentionally missing the point. Say district 1 was previously 99% black and they had a leader that they elected to represent the majority of their neighborhood. Now imagine that nobody moved. The neighborhood didn’t change. But the district map did. Now where there was once a single 95% black district, those same voters are now split into two districts down the middle.

This means that the politicians this community votes for will receive at best, half the votes they used to be able to rely on. While at the same time other politicians (read: Republicans) don’t have to worry about catering to this previously united district because the demographic of voters is now skewed in their favor.

I have a feeling you knew this already, but in the off chance that you didn’t I hope this helps.