Spaghetti westerns were also a kind of reimagining of classic westerns, which themselves were American period theatre set with horses and saloons rather than streetcars and drawing rooms. The violence is an integral part of the yarn because the films are set in a brutal environment where guns were used to settle things. The idea is similar in Jidaigeki/samurai films. Just substitute swords for guns.
KungFu films whole reason d'etre is martial arts, that's the centre of the film, with the story , for what it's worth, used to set up tthe action bits..
I can recall the stories and plots of a lot of westerns but am hard pushed to do so with Kung Fu films.
I'm just thinking out loud but my views are something along these lines.