It's not uplifting, it is a parable of karma. It is posing the claim that we are all one life, and you should seek to uplift all of humanity, because you will live every life, even the lowest.

Or that you should uplift the best life of humanity, because you will live it.

But generally, work for a distribution that you would prefer.

It is a spin on Bentham(?)/Rawls(?) Philosophy that you should choose a social contact/morality that you'd find acceptable if you didn't know who you would be born as.