>OP has not stated this directly but come very close, implying that members of race X, for whom their race is part of their identity, will support opinion Y if such is preferential to members of their race.

You've just described demographic research.

Prejudice is defined as such:

preconceived opinion that is not based on reason or actual experience.

>At its core this is still prejudiced. Op has thrown a zillion cultural confounders and nuances to the wind and presented an argument based totally on race.

Reductive perhaps, but not prejudice.