While I think that helping those less well-off is a good thing, I don’t think it’s an ‘imperative’ like the OP apparently does. Helping someone get over a tough time, or someone who really cannot help themself is one thing, but simply giving handouts to those who don’t have any desire to do any work of their own is bad, as it prompts them to simply ask for more instead of bettering themselves.
Third-world countries are generally looking for handouts in this day and age; the governments of said countries routinely take aid money and supplies, use them for themselves and not ‘the poor’ in their country, and then point to the people they kept aid from or the lack of infrastructure (from spending loans on building palaces instead of said infrastructure) as a basis for getting more money or loans forgiven. The overall effect of the ‘aid’ is to let the people in charge ignore the consequences of their actions and motivate them to maintain the status quo instead of moving their country into the 20th (much less the 21st) century.
If the ‘moral imperative’ types REALLY wanted to help the poor in 3rd world countries they’d support funding either revolutions or conquest of said contries, followed by a ‘Marshall Plan’ to build some basic infrastructure and education into the countries. Since they won’t support that, I can’t see any basis for what is effectively funding oppressive governments and would say that we have a moral imperative not to send any ‘aid’ their way.
There are a variety of countries which have managed to massively improve their living conditions, but as long as a given country has virtually no education and a very poor system of law, it is simply not going to become wealthy, and tossing a little food at such countries will only ensure that you have to continue tossing that food at future generations.