Jan: Now you're changing the subject. Why don't you give away your riches to the poor?
Hardenberg: Simple. Because they're strangers and I don't owe them anything. It may not be their fault that they're poor, but it's certainly not mine. And unless you quit being a bum, get the highest-paying job you can, and hand over all your earnings above your basic needs to the poor, you're going to have to give same answer.
Which reminds me of nothing so much as Dr. Caplan's position on immigration, viz. that the world's poor would be better off if they immigrated here, and that we have the duty to take their plight into consideration. My reply to that is exactly what the rich man says: why is it my problem? "They're strangers and I don't owe them anything. It may not be their fault that they're poor, but it's certainly not mine."
Suppose two men, John and Julio, are heading to a job interview. Julio tells John: "I need this job more than you do. Please drop out of the race so I get it." It's perfectly reasonable for John to make Hardenberg's reply: "No. You're a stranger and I don't owe you anything." At this point, Mangan and I are in full agreement.
But suppose instead that John handcuffs Julio to a tree to prevent him from going to the interview. Julio says "Let me go. I deserve a shot at this job too." At this point, it's ludicrous for John to reply, "No. You're a stranger and I don't owe you anything." Julio isn't demanding help; he's just demanding that John leave him alone. And if John were to object, "You're not leaving me alone. That job is MINE, and you're trying to steal it from me!" we'd have to answer, "The job isn't yours. It's up to the owner of the business to decide who he wants to employ."
All of this is obvious to any upright 10-year-old. You're under no obligation to give your toys away to less fortunate kids, but you're certainly not allowed to steal toys from less fortunate kids.
Unfortunately, if the victims happen to be born in another country, most adults don't have the moral sense of a 10-year-old. Don't want to help poor foreigners? Fine. But at least leave them free to sell their labor to willing employers, rent apartments from willing landlords, and buy goods from willing merchants.