Lmfao. It's the opposite. It's on idiots trying to say Shanks isn't one, when he is literally seen with a sword everytime, pulls his sword everytime he's about to fight, is a rival of the world's strongest swordsman, has no other powers, etc. So if you can please point out why Shanks isn't a swordsman. Of course, as I already said, you can't and even if he threw a kick, punch, or whatever, he'd still be a swordsman thus inferior to Mihawk.
Mihawk wasn't the WSS from his mother's womb. Roger, Rayleigh, Xebec, etc, have nothing to do with Mihawk being the current strongest swordsmen. But Shanks a swordsman does. And so he is inferior to Mihawk.