Obvious issue: the man is not "swarthy". He's a bit sun-touched red, but definitely not "dark-skinned", as "swarthy" means.

The Japanese nameplate for this NPC is 威勢のいい船員, which translates roughly to "Sailor with much vigour". I've also seen it translated as "Dashing sailor", while I'd personally translate it to "Jolly sailor".

My speculation is the English localization team assumed "swarthy" meant something like "rough and ready", without actually looking up what "swarthy" means, or why "swarthy" as an adjective is often associated with "rough" and other descriptors of lower class.