It's so disappointing that you have made the mistake of thinking that those two possibilities listed cover the entire set of possibilities.

The Parable of the Polygons is a cute case study that shows that it is possible, in a mathematical sense, to prefer diversity and yet end up segregated: https://ncase.me/polygons/

The whole point of studying institutional and structural racism is that no one needs to be racist per se to have racially discriminatory outcomes. Perhaps a good analogy is the higher mortality rates among left-handed people. We no longer persecute them and drive them out of society or beat them for their sin, and yet, they die earlier due to structural factors.

I agree with you that "people don't like other people believing they-en-masse discriminate." And that's why science in the US is f*(&ed, because somehow everyone takes intellectual inquiry as some sort of personal affront or verdict on individual virtue, and that's the one thing the American cannot abide, the thought that someone else is judging them and finding them wanting.