"No man is a stranger. You accost anybody. Warm and confiding, you wait not for measured advances. And though, indeed, mine, in this instance, have met with no very hilarious encouragement, yet the principle of a true citizen of the world is still to return good for ill." (24, 10)
Frank is explaining what it's like to be a cosmopolitan. The main job requirement is to be ready to be awesome to others, even if they're bags of doo-doo to you. That's some major charity, in the form of generosity of spirit—and it's a fairly tall order.
"Is the sight of humanity so very disagreeable to you then? Ah, I may be foolish, but for my part, in all its aspects, I love it. Served up la Pole, or la Moor, la Ladrone, or la Yankee, that good dish, man, still delights me; or rather is man a wine I never weary of comparing and sipping; wherefore am I a pledged cosmopolitan, a sort of London-Dock-Vault connoisseur, going about from Teheran to Natchitoches, a taster of races; in all his vintages, smacking my lips over this racy creature, man, continually. But as there are teetotal palates which have a distaste even for Amontillado, so I suppose there may be teetotal souls which relish not even the very best brands of humanity." (24, 12)
Frank is shocked—shocked—at Pitch's serious lack of interest in making nice with the world. Cue his chance to talk about how much and in what manner he loves mankind. In this description, we can't help but notice how he's using a lot words associated with tasty snacks. More accurately, beverages. Come to think of it, he loves all the people of the world after "sipping" these great "vintages." Is this a realistic point of view, or is Frank kind of a smarmbot?
"A cosmopolitan, a catholic man; who, being such, ties himself to no narrow tailor or teacher, but federates, in heart as in costume, something of the various gallantries of men under various suns. Oh, one roams not over the gallant globe in vain. Bred by it, is a fraternal and fusing feeling." (24,10)
Frank puts in a plug for not being a man-island. Travel the world, folks. It's a brotherhood. See and meet and chat with everybody. This type of roaming connectivity is the ultimate freedom, and isn't freedom what people are actually trying to get with the solitary life?