So once again One Piece wankers fail to understand actual premise behind dialogues.
Try to look at statements with nuance and pay attention before pushing agendas for once
Zoro: I see...so you're some sorta killing machine huh
King: Is there a need for stuff like styles & forms in battle?
Zoro: Well, I guess that's true...!!
Zoro: You didn't refer to yourself as a swordsman after all
Zoro: Do as you will!!
Zoro: I too might just bite your throat off...
Zoro: ...when I deal the final blow on you
Zoro: I can't afford to lose...!!
King is telling Zoro, the goal of a battle is to win, not to have a fancy fighting style. Its an everything goes death match to which Zoro said he agrees and says even he himself would do shit like biting King's neck.
Of course King is a swordsman because he wields sword and knows how to use a sword pretty damn well. That doesn't mean a swordsman fighting another swordsman can't kick or punch or bite.
You fight to win
You fight to Kill
And by winning the fight with the strongest, you become the strongest
If anything this destroys the notion of most skilled swordsman as Zoro himself says its fair that King can use tricks in a battle.