It's a deviation from the spiritual ideal, and probably from authentic tenants of the faith (about which I know very little--but scholars and clerics among both Buddhists and Muslims have acknowledged commonality).  There is an old Muslim proverb: "The difference between Islam and Muslims is the difference between a pearl and an oyster."  It appears the same can be said for Buddhism vis-a-vis Buddhists.  And as Ibn Hoor points out below (don't take offense, ya' Yudah, I merely Arabicized your name, intended as a compliment), Imperial Japan's Bushido Code is another--and a horrific--example.  It was as nightmarishly barbarous as the worst Wahabbi-spawned cult centuries before it expanded beyond Japanese shores.