That's isn't libertarian.
That's, at best, the caricature of a right wing libertarian (I'm not sure that it appropriately represents them, tbh).
Are you saying that your view of Libertarianism is more correct than mine and that under libertarianism I have responsibilities to others I don't know and have never met and need to contribute to their well being? How will I do this? Perhaps via centrally organised tax? Or an enforceable duty to work for others?
How many of these other less fortunate people do I have a duty of care to? All of them? Or just those up to a certain distance away? We could nominate distances and call them borders and everyone within that border I have a duty of care to. But how would we stop people crossing that border? Border guards! Now, how do we pay them?