In corporate and academic America diversity unofficially means not majority white. Further, you're not supposed to acknowledge any sort of ingroup bias of any nonwhite racial group

It isn’t the “opposite” because this isn’t a binary situation. There is a spectrum. If the group members were all from the same place it wouldn’t be an issue either. If everyone is from different places it isn’t an issue. If many are from one place and some aren’t, then it is an issue.