For reasons of morality I think the better off should feel they must help their struggling fellow human beings. And that can only be fairly done via government arrangement.
But the appropriate portion of GDP is difficult to agree on, the differential between the least and most generous ought not be massive as then either someone is not "pulling their weight" or someone else if playing "Lady Bountiful". We are all in this human race together.
For sure one ought not put oneself in debt in order to give to others, but since it is all a question on management, who is to say when a charitable donation is causing overspend, or spending elsewhere in the budget where someone is "not cutting their coat according to their cloth".
We are part of the richer West and an economic power too. If we can't help then how can we expect others to ? What are folks (who agree there is a moral obligation to help) opinions on an appropriate percentage countries should give ? Are we too generous or are others avoiding responsibility ?
Then there is the problem of targeting aid properly, so many stories of foreign elites grabbing it for themselves.
Such a complex issue with many parts to be decided, if one takes the issue seriously.