The key here is >which may result in competitive injury It is, in short, "you can't sell an apple to your favorite customer for 20% less than other customers

The key here is >which may result in competitive injury It is, in short, "you can't sell an apple to your favorite customer for 20% less than other customers just to help them kill off their competition." All the rest is just hurdle-clearing to address various defenses to the "this was pure competition-killing." It's an anti-trust law. Price discrimination without anti-competitive traits is legal ("Price discriminations are generally lawful, particularly if they reflect the different costs of dealing with different buyers or are the result of a seller's attempts to meet a competitor's offering.")