That you think whites were advantaged is a rational argument for you to personally give black businesses preference. Government, however, should never discriminate in any direction
Wrong. Again, government is not just obliged to just "think whites"
this or that. It's obliged to monitor the situation with respect to minorities, then act to correct any
systemic problems it identifies. Where it's become clear that qualified blacks are applying but not being hired as firefighters, for example, then government is morally and legally obliged to take corrective action. Discriminating against qualified white applicants as needed to balance the level of opportunity. Personal choice doesn't enter into it.