He literally doesn’t lmao
Hmm cant believe I am saying this but you are actually right. Even in the panel you showed zoro, actually never acknowledged him as a swordsman. Going back to the chapters in the VIZ he actually explained why. It was because cabaji was using under handed tricks / fighting dirty.
So zoros criteria of being a swordsman is :
Being strong
Fighting with a sword
Not using underhanded tricks
Using haki, martial arts, devil fruit ability along with your swordsmanship does not discredit you from being a swordsman in his eyes. Its using under handed tactics that does.
So zoros criteria for what a swordsman is,is not as vast as people think it is at all.
In zoros eyes king (special race, devil fruit user, haki user, fights with brace knuckles and kicks , also has a sword) was considered a swordsman by his definition
Mr1 (devil fruit user, martial artist, body made of blades) classified a swordsman.
By zoros definition law, fujitora, Shanks, s-hawk, bigmom are all swordsman. Especially since none of the following above even denied them being so. Only the fans