Fujitora law were called swordsmen by oda
I think the problem isn't who gets labeled as a swordsman and who doesnt, but rather the definition of swordsman as a whole.
The argument with King is that he doesn't have to be the strongest "swordman" Zoro has encountered thus far as an enemy, but rather just the strongest enemy because he fights beyond the use of his sword and just is a 1.x billion beri pirate who is Kaido's #2
This really comes down to the whole argument about Mihawk. For sure, Mihawk is the WSS, he can very clearly trump anyone intending on using a Blade against him in combat. But now its very clear that when you have characters like King, who don't even fit into the mold of being a "true" swordman by fan definitions, how can we say anyone else does as well?
For example, Kinemon could be a far better swordsman than Law, but Law's devil fruit techniques are what give Law a totally different combative style to defeating opponents. Does that give Law an advantage beyond being a sword user?
It's also the same argument that can be made with Shanks, because at the end of the day,
we don't truly know how Shanks fights beyond a few clashes with his blade. Ive made this argument before, because yes at the end of the day Mihawk is the better swordsman probably, but that doesn't mean someone like Shanks or Whitebeard or Big Mom or anyone else couldn't just drop their sword and fight a different way. There is no "clearly" defined definition on how Mihawk surpasses these people outside of sword technique.
And that's why King is the perfect example of this. He uses his sword in 1 way, but then throws a punch or kick
because he can
At the end of the day, Zoro and Mihawk will probably fight exclusively with their blades, which will define who is the WSS. That doesn't mean other pirates with blades have to even follow that rule. That doesn't mean Mihawk is stronger than Shanks, because we don't truly know how Shanks can or would fight beyond his blade. We have othe Yonko forgoing their weapons to fight with their powers or their bare hands.