Some of this myth regarding protein replacement after workouts is coming from the endurance athletic sector.
Endurance workouts can run anywhere from 30 minutes to 6+ hours (With the longer workouts needing supplemental food/fluids during training to avoid complete depletion, aka "the bonk" {which is another very misapplied term/concept}). Once you are finished with this, you need to replace basic electrolyte stores as well as muscle glycogen and fluid.
Due to heightened insulin sensitivity, there is a 30 minute time frame post workout where the body will most readily move nutrients into the cells for replacement. Usually an easily digested carbohydrate of some sort is recommended. Studies have been done showing that milk, with a 3:1 carbohydrate/protein ratio is ideal, and easily matches or outperforms every recovery drink on the market.
When you stress the muscle fibers for repair, your body generally has everything it needs to repair and improve the muscle fibers damaged during the workout. As Berin stated and answered, this is a longer process than just the hour after a workout, and can easily be supplemented by a healthy diet and protein intake over the next day.