I haven't read the book referred to in the article but I've for example read Mishima's Runway Horses - which also draws on historical circumstance from the Shinpūren Rebellion (1876). https://en.m.wikipedia.org/wiki/Shinp%C5%ABren_Rebellion

Does that not exemplify similar values as us (Westerners) expect from the term 'Bushido'? Was the former a very rare isolated incident and not actually representative of samurai ethos?