> technology that's not that expensive
"Expensive" is relative, and the technology has extra costs outside of itself that have been paid in some parts of the world, but not in others. In a part of the world where electricity may as well be unobtainium, that heavy, carefully-calibrated, $1000 centrifuge isn't much better than the scrap value of the metal it's made from (while still being obscenely, prohibitively expensive for the people it would help).
> justify our actions
Who's talking about justification, besides you? There isn't anything to justify.
> Are we really that developed?
We've got shinier toys, if you want to call that "developed". We haven't improved upon the human race itself, if that's what you mean. Humans are naturally selfish and tribal. Society shifts tribal boundaries, and social structures like government can force selfishness into a longer-term view, but that's about all.