Pro bodybuilders have two things that your average person does not:
1.)amazing muscle building genetics
2.)drugs
These two things allow them to train whatever the hell way they want to.
What works for them is probably not going to workout for your average person.
Now let's pick apart the workout scheme from looking at it in general:
1.) It has you train 6 days a week with weights. Where is the recovery time? One day off every sunday? Ridiculous
2.)54 sets per workout. That is a ridiculous way to train, you're going to have to train at such a low intensity to complete all those sets. That's horrible efficiency.
3.)This would lead to overtraining so fast.
Now to the bodypart bit:
1.) It isn't physiologically sounds because, a.) when the body performs a movement with resistance, you can't choose what muscles are being worked, there are several muscles that come into play and it is inevitable. Example -
Workout A says it is trainings your quads, then it gives squats as movement used. Well, the glutes and hamstrings are also involved in the squat to a pretty large extent if you are doing them properly. Next day it says to train hamstrings. Well, they were just trained the day before...and what is this? The only way you are training your hamstrings is doing the single joint movement leg curl. The leg curl does not train the hamstring as well as a squat trains the quad. There is no hip extension involved in this program, things like RDL's will train the hamstring in a more effective and functional way because they body works in multi-joint movements, not in isolation. Also, the leg training is out of balance.
2.)Then workout C has you train your shoulders/tris, then the next day it has you train you chest. Well during the chest press your shoulders and tris play a huge role. Because remember - the body works in movements. The shoulders/tris are involved in all pressing movements to some degree, some greater than others. Then when you don't compensate for these kind of things it can lead to overtraining and imbalances which lyes in the very workout you linked us to.
Hope that helps.