I am pretty sure that - if your aim is to try and ensure our descendants colonise the galaxy successfully - then helping the needy in Mozambique is not going to be the best way to do that.

I myself do have this aim :-). See my response to a comment by taw.

What is the supposed aim of this "good quality" charitable giving? Presumably there is no generally agreed-on one - and different participants pull in somewhat different directions.

Could be. I think that many/most people have some utilitarian impulse in them and this is what I was appealing to in my article.