Judges SHOULD NOT discriminate on colour.
We had a debate here in NZ a few years ago about paints and "coloured" horses being placed below the solid colour horses.
A horse should be placed (if its worthy) no matter if its chestnut, palomino, black or pink with purple spots.
Some judges here, felt they had to place coloured horses below, because they thought over seas judges may look down on them for placing a coloured horse, this discrimination was happening in dressage, showing, show hunter and pretty much all the english diciplines where there was direct judging of how the horse goes, looks etc.
sorry if that makes no sense :P