I first came across this poem as an adult and assumed it was satire, or at least some sort of sarcastic denunciation of imperialism. I enjoyed the image of empire being the bane of the imperialist's existence. We were never force-fed Kipling at school so other than the children's stuff I heard nothing of it and as a result was unaware of the man's views.
Over the years I had come across various Kipling tales and viewed them as something of his time, when the natural order of things dictated that whiteness was goodness and deviation from that purity was reflected directly and proportionately in the character and entitlement of the individual. These things were not of our time and we could safely ignore them as long gone.
I've learned a lot since then. I realise now that Kipling was expressing the effect of imperialism, not on the imperialists but on those who are charged with enforcing their will. The people at the bottom, whether oppressor or oppressed are equally dispossessed. Kipling was on the side of the oppressor in this poem, while decrying the cost (some irony there) He gives us no answers to the obvious questions raised and the call to sacrifice is not one that we would willingly honour today, but the recognition that there are no winners in the imperial game should give us a reason to see the glimmer of humanity. I wonder what Kipling would have written after 1919, after the death of his son in the mud of France.
I don't know who said it but one definition of a first class mind is its ability to entertain two thoughts without agreeing with either of them. I would modify that to say that a first class empathetic mind can entertain two worldviews without agreeing with either. And further, learn from them both.