Faulty logic is faulty logic, though I do agree with the end result. Shang Chi is an absolute fighting master. The kung-fu thing doesn't mean he only knows kung-fu... He's knowledgable in many different styles. His father was said to be a master of "all styles", whom Shang ended up defeating. He IS Marvel's Shiva, not because he is equal to Shiva, but because he's generally regarded as the best straight up martial arts expert in Marvel, where Shiva is the same in DC.
The kung-fu thing doesn't mean he only knows kung-fu... He's knowledgable in many different styles.
Good point. At the time he was created and being featured monthly in The Hands of Shang-Chi: Master of Kung Fu during the 70s, Kung Fu had, in America, become largely synonymous with all martial arts. If someone was putting a beat down on another guy, no matter what style he was using, actual Kung Fu, or Karate, Judo, no matter what, it was considered Kung Fu. It just sounded cool, and had been incorporated into the American consciousness because of the movie craze at the time.
Shang Chi is not limited to the singular and related disciplines of Kung Fu, but is a practitioner of a wide and varied range of martial arts. He was trained by Fu Manchu and made to be the ultimate fighter and conqueror, despite the path of peace he has chosen, he retains and practices all of those skills. Rogers is done.