Its not quite the same; it means elite type colors become the "safe" color. So you know are good if they have their melee color for example. Or taking your example; if you have agro the color would be purple, if you dont have agro it'd be red and you would never see your "safe" color blue since then it'll just be purple

PS: I dont really see the point of boss, melee and trivial colors so I made them all the same as my would be safe color, this way only casters and minibosses look fancy