Not sure what you're driving at...
I don't think anyone here believes that it is not reasonable to help people when they need it, depending on circumstances (and that's a major qualifier). The kind of examples you give cost very little, and help people out a lot.
Although libertarians have sometimes been described as people who wouldn't catch a kid falling out of a tree unless he was paid, this is not true.
Heck, even Ayn Rand approved of generosity, or "benevolence" as she called it, but did not consider it one of the major human virtues. Other objectivists, like David Kelley, believe it has a more prominent place in that philosophy.