[The mention of "thief" reminds him of Nami... and whether or not Lupin realizes it, earns him a point in his favor by vague association. He side-eyes the hand and then gives it a firm shake.

As for the question:] Pirates gotta eat, too, and someone's gotta feed them. [A shrug, and even a slight tip of his lips into a smirk] Running from the shitty marines and cooking are both full-time jobs.