You sure do have issues trying to flame bait with people. But Sanji was trying to fillet a fish he hasn't cook before, so him trying to figure out something isn't being useless and so what if Zoro had to help him? You got a problem with Zoro helping his friend?
I don't find issue for zoro helping sanji there. We know sanji was stuck there on the challenge and zoro showed sanji how to solve the challenge. Just something like a master giving advice to his student