No, there is no legitimate and illegitimate swordsman. There is a swordsman and there is a non-swordsman
Oda gave the explanation for this already. Oda had King directly say him NOT using sword techniques and sword styles is what makes him a non-swordsman… And Oda even demonstrated it in the fight
even when King pulls out his sword and wins a sword clash with Zoro, King NEVER says a Sword technique name…. when King is in Hybrid Zoan form and tackles Zoro, he calls out an attack name… When King is in full zoan form and pulls his head to launch a headbutt, he calls out an attack name… when King is in Base form and manipulating his fire abilities to launch Magma-fire dragons, he once again CALL OUT ATTACK NAMES… The one and only fighting style that King uses that he explicitly NEVER USES AN ATTACK NAME is when he pulls out his sword… And again, you can’t even say that it’s because he’s not good at using his sword, he straight up wins a slash against Zoro with his sword so he’s obviously good at using it
Oda just makes sure to have King define what a swordsman is, and then he demonstrates it in the fight what makes king not a swordsman
I think this is it. This is the end of the discussion. For Oda to make a character a non-swordsman, he simply has to not make them use Sword techniques. That’s it. And unfortunately for the agenda warriors here, all their favorites very clearly use sword techniques all the time