The Book of Lord Shang can be considered a forgery in as such an 1800 year old book is not as good as the 2100 year old book. The passages within were likely authorized by different people at different times and is most likely a compilation or distillation rather of several legalist philosophers some few centuries after Shang Yang had died and posthumously attributed to him. Some verses may even possibly have been authored by Shang Yang himself though it is impossible to be sure.  
 
One of the contradictions of the legalist school lies in their highly developed monetary system which was at odds with their surplus-destroying economy based principally on corvee labour and agriculture. Then again as Lewis believed, the Qin state at least was one geared towards perpetual war and eventual self-destruction so a certain intellectual consistency isn't necessarily required.  
 
The book ironically shares the same fundamental value with libertarianism, that is the recognition that a strong state must inherently come at the expense of a strong people. In Shang Yang's case, he believe's that this is the way the world should be ordered, and bluntly enough, entitled the paragraph dealing with the relationship between state and people simply as "weakening the people".