How do the colonial subjects repay their masters in Rudyard Kipling's poem "The White Man's Burden?"

One of the major themes of “The White Man’s Burden” is the idea that the white people go out and have to work hard to civilize the non-white people without any gratitude and often without much success.  This is how the colonial subjects repay their masters.  They repay them by resenting them instead of appreciating what they do.  They also repay them by destroying (even if they do not do so on purpose) the things that the masters are trying to achieve.

One of these ways that the subjects repay their masters is found in the third stanza.  There, Kipling tells us that all the work that the white people do will end up being for nothing.  They will work hard to try to end famine and war, but it will not work. The reason for this is because the subject people will ruin what the masters are trying to accomplish.  Kipling tells his white audience that

when your goal is nearest
The end for others sought,
Watch sloth and heathen Folly
Bring all your hopes to nought.

In other words, he is saying, the subject people will repay their masters by spoiling everything they have been working for. The subjects are lazy and foolish and they will therefore ruin all the good work the whites are doing.

The second way in which the subjects repay their masters is found in the fifth stanza.  There, Kipling warns the white audience that their subjects will not appreciate their efforts.  The white people will try to pull the subjects “(Ah, slowly!) toward the light.”  This means that they will try to civilize their subjects even though that is difficult and it takes a long time.  However, the subjects will not be grateful.  Instead, they will resent the efforts of their masters.  As Kipling says, they will hate and blame their masters and ask

"Why brought he us from bondage,
Our loved Egyptian night?"

From these two stanzas, we can see how the subject people will repay their masters.  They will repay them by ruining (even if they do not mean to) all the things the whites are trying to do.  They will also repay the masters by hating and resenting them.  This is part of why, Kipling says, imperialism is such a burden on the white people.