The fact is, that civilization requires slaves. Unless there are slaves to do the ugly, horrible, uninteresting work, culture and contemplation become almost impossible.
Just as the worst slave-owners were those who were kind to their slaves, and so prevented the horror of the system being realized by those who suffered from it, and understood by those who contemplated it, so, in the present state of things in England, the people who do most harm are the people who try to do most good.