But mandatory minimums just raise the stakes of prosecutors choosing among overlapping potential charges based on affinity, and remove the ability of courts to compensate for that. So they do the opposite of preventing sentencing based on affinity,by changing the point of the process in which affinity applies to dictate sentencing.

Taking common sense and judicial discretion out completely is not the best way to achieve equality. It is the socialist way, if I can make the analogy - fighting inequality by making everybody equally poor (or, in this case, equally oppressed by insane sentences for minor crimes). Making policy changes that prevent anybody from getting insane punishments for minor crimes seems much better alternative to me.