First, the Bushido code was implemented during the Tokugawa Shogunate, a 250-year peace period, in an attempt to control the behavior of the Samurai, a highly trained fighting force with now no enemy to fight. It had no place during the Sengoku Jidai (Warring States Period). But I guess rape, pillaging and murder isn't acceptable if they're not in some far away land on campaign?
However, I find issue with karateka using the Samurai for marketing not for the hypocrisy of it (although that's a big factor), but rather the fact that it's historically incorrect. The Samurai had absolutely nothing to do with the development of karate! The Samurai were the military nobility of feudal Japan, the middle and upper echelons of the warrior class (abolished in 1868). Each clan had their own proud tradition of combat styles, and the history of koryu Japanese martial arts is well-documented. Jujutsu was the most common unarmed fighting style of the Samurai, one of 18 fighting disciplines (called the bugei juhappan) that they were expected to train in. Karate wasn't introduced to Japan until at least 1921, 53 years after the abolition of the Samurai class. But that doesn't mean that karate doesn't have a proud warrior history of its own.