Martial arts school martial masters actually don't understand the "matters of Jianghu." To them, heroes and those from the Green Forest are all thugs—if there has to be a distinction, it's that "heroes are on average much better than those of the Green Forest, with no lackeys"; other than that, the differences aren't significant.
On the side of the Protectors, "Kings" is also not a common term. The structure of the Protectors is very loose, and the influence of superiors over their subordinates is limited. Many important figures don't impact the commoners in their lifetime (or if they do, the commoners wouldn't know).
But the term "His Highness, the Fire God," which doesn't trigger key-word alerts to attract crawlers and points so obviously, makes everyone understand implicitly.
