It's completely relevant but its all answered below.
There is no "as a swordsman." Mihawk is above Shanks period. It didn't matter for any of Zoro's battles so how come it matters for Shanks?
Once again, it doesnt matter. Lots of Zoro's opponents had abilities beyond swordsmanship but Zoro didn't care and had to overcome all of it to be stronger than them.
Fujitora is a strong swordsman because of gravity....Law because of the Ope....Diamante because of Flutter etc...
There's also no report on Shanks beating Mihawk but the latter is the one with the title
There's also no report Katakuri being beaten before Luffy or Roger/WB beating the other.....so any statement relating to their strength is irrelevant?
Mihawk doesnt like fighting against people with handicaps. It's nothing but an honor code that he and Zoro shares and displayed.
It's irrelevant whatever other abilities Shanks has just like how it was irrelevant for most of Zoro's opponents and even Zoro himself. That's the point.
As you can see, I didn't misconstrue a thing.
Its not bias to say the strongest swordsman is stronger than a swordsman......
Instead, you could have said: Whitebeard was the STRONGEST man yet Roger was his equal, contradicting his title. WB and Roger fought many times but it's unknown if there ever was a victor. To be the new WSM, you have to beat WB and have it publicly known. With that alone, you'd have a decent example for Shanks and Mihawk. Mihawk is the WSS and one has to beat him to claim the title....Mihawk and Shanks fought many times but if no one knows if Shanks won or if they fought to a draw, Mihawk would be the WSS. Shanks became stronger after he lost an arm? Doesnt matter since Mihawk and Shanks has interest in fighting each other, with Mihawk keeping his title unchallenged as a result. But you then have to explain why Mihawk is waiting for an opponent stronger than Shanks.