Yes the muscle split routine is geared for the advanced lifters because we have the abilty to apply more intensity per muscle group than beginners (0-12 monhts). Intermediate lifters ( 6-18 months) can usually look for a moderated upper/lower split to give themselves a beginning level muscle specific workout to gear up for the more advanced major muscle group split. Depending on how advanced an intermediate lifter is ( 18-24 months), they can start looking at a muscle split routine if they feel they are ready for one.
If you notice, I leave an overlap of about six months in each level becuase some people advance more rapidly than others by various means and reasons. each level can be split into three sub-catagories ( beginner, intermediate and advanced) and three main catagories.....beignner, intermediate beginner and advanced beginner, so on and so forth up the ladder with the other two main catagories.
The main reason for not advancing too quickly is that the more advanced you get, the more specific you train....and the more isolation moves you place in yoru workout, as well as supersets, drop sets, negatives, forced reps, ect. Lower level trainers should not worry too much about isolation moves, and should stick to the bulk of compound movements to get the most out of their workouts, working on form, progression up the weights and learning how their body works and the exercises applied to it (what works best and what does not).
Ive seen too many people jump in over their heads with advanced routines and get nowhere because their body is not matured enough in lifting to handle them. I was one of them the first year of my lifting life in my late teens. Monkey see, monkey do, the basic gym rat mentallity.....bench , curl, bench curl, bench, curl maybe legs and some back if I felt like it. Clear as mud? lol
Desire, Dedication, Discipline